I've had two new acquisitions since my last post: a venerable Hasselblad 500 CM and a Rolleiflex 6006.
Anyone with a knowledge of photography should recognize the Hasselblad brand. It is associated with quality, reliability, and repairability. The quality of the Zeiss lenses that Hasselblad uses are another significant factor as to why Hasselblads are so highly regarded. I won't go into a lot of detail about the Hasselblad as there are many posts and articles about the classic Hasselblad V system cameras, but here are the high-level details.
The Hasselblad 500 CM is an all-manual system requiring no battery for any of its operations. The lack of reliance on battery power means that it's definitely one less thing to worry about in the field. That also means it does not have any built-in exposure metering, requires manual winding of the film, re-cocking of the in-lens shutter, and return of the mirror into its 45 degree position. It's also compact (for a medium format camera), but has a good, solid weight to it.
The Rolleiflex 6006 is a lesser-known camera compared to the Hasselblad, but is no less of a slouch, and is definitely the anti-thesis of a Hasselblad in terms of "manualness".
Most photo aficionados are familiar with the Rollei name in the form of the small-format Rollei 35 and the highly-regarded Rolleiflex TLR (twin-lens reflex) cameras. The Rolleiflex TLRs featured Zeiss and Schneider Kreuznach lenses. Again, most are familiar with Zeiss, but not so much Schneider Kreuznach. The Schneider Kreuznach lenses suffer from lack of brand recognition, especially in the U.S., but do not suffer from quality in comparison with the Zeiss lenses. That is also inherently the problem with the Rolleiflex SLRs.
Rolleiflex SLRs are very much in a class of their own. When the 6006 was introduced in 1983, there was no medium format camera that had the level of automation and ergonomics in the market. The controls on the 6006 were intuitive, with dual shutter release buttons for either left or right-handed use. It has a built-in motor drive shooting at 1.5 frames per second. It has TTL center-weighted exposure metering and TTL OTF plane flash metering, all within the camera body, not in the viewfinder. The film magazines had built-in, retractable dark slides, and completely reversible film spools. The bayonet lens mount had electronic contacts like the Canon EF lens mount, but came out a full 6 years before Canon introduced them to the 35mm world. Back in 1983, this was a very advanced camera.
Now, 30 years later, the Rolleiflex 6006 is finally out-classed by the Mamiyas in terms of automation, but not in the 6x6 world. The Mamiya 645AFD is certainly a top of the class in the 6 x 4.5 arena, but the newer Rolleiflex SLR cameras like the Hy6 and 6008 Integral Mod 2 are far and above the state-of-the-art medium format cameras of the current generation.
The lenses for the Rolleiflex SLRs and even for the 6006 utilize either Zeiss or Schneider Kreuznach designs. Even the cheaper, "Made by Rollei" f/2.8 80mm kit lens, while not owning the Zeiss label, utilizes the Zeiss Planar design and is by no means a slouch. All the lenses are leaf shutters which can provide flash synchronization at any speed up to 1/500 second, and even higher with the PQS (Professional Quality) lenses, though PQS lenses cannot be used with the 6006.
All this automation is powered by a rechargeable battery, albeit with lower-capacity Ni-Cad cells. There are plenty of modified batteries available that can re-cell the batteries to use Ni-MH cells with the Rollei N charger or custom chargers.

The Pentax 6x7

Recently I added another medium format camera to my collection -- a new (to me) Pentax 6x7. Now this isn't the first time I've owned this model of camera. I actually owned one several years ago but sold it because I needed the money.  Since I've been building out my collection, I've had a hankering to get this camera back. What do I like about this camera that made me get it twice? The first time I owned this camera I was a photography student and wanted to have experience with medium format. There were so many options that looked very similar. If you look at medium format cameras, they all look, behave, and feel similar. Bronicas, Hasselblad, and Mamiya are all basically shaped the same. They all start out with a mirror box body, the film backs are similar in function and form, the shutter is in the same place, and they all start with waist level finders. Folks who own Hasselblads will probably recoil in horror that I lumped that brand of camera with Mamiya and Bronica, but in terms of basic form, they are comparable, but the comparisons will end there without further discussion.  What is obvious about the Pentax 6x7 (and the newer 67 model) is that looks like no other medium format camera. It is an overgrown 35mm SLR camera. The closest competitor is probably the Mamiya 7 line of cameras, though the Mamiya model is a rangefinder rather than using a pentaprism for image framing. I figured, at that time, was that the transition from 35mm to medium format would be eased because of how similarly the Pentax 6x7 looks and handles like a 35mm SLR camera.  Whether I was right or not is debatable, but the camera handling is so effortless that the transition was smooth.  What the Pentax gains in ease and familiarity of use, there are certainly trade-offs: This is a HEAVY camera. It weighs about 6 lbs with the camera body, prism, and lens. Imagine, if you can, hanging this camera around your neck (which i do not recommend). this also means that this camera is built like a tank. If there's any plastic in this camera, you'd be hard-pressed to find it.  This is a LOUD camera. The sound of the huge mirror slapping and returning will awaken the dead. Because of this, camera shake due to mirror vibration is a possibility, which is why Pentax came out with mirror lockup functionality after the initial release of the camera.  Similar to the Pentax 645, there is no interchangeable film back for the 6x7, so unless you absolutely love changing films mid-roll, you're stuck shooting the entire roll of film. The great thing about the 6x7 is that it can accommodate 120 or 220 film sizes without any adapters. You merely need to slide the pressure plate on the camera back to the film size you're shooting.  Lastly, this camera is SLOW. the maximum flash sync speed is 1/30th of a second, due to its massive shutter curtain. No, unlike the Hasselblads, the Mamiyas, and the Bronicas, save for a few lenses, the 6x7 lenses do not have leaf shutters built into them. This doesn't make it ideal for studio work, but then I've never had to use a flash with it.  So I mentioned that I sold this camera, and then I went and reacquired it (not the exact same one, but similar). I had acquired other medium format cameras like the Mamiya RB67 and a Fuji GX680, which were box-type medium format cameras, but I had missed my Pentax 6x7. It was so much easier to handle. The RB67 and the GX680 are the heaviest medium format cameras ever produced, and I'm sure the 6x7 is close to their weight class, but the 6x7 is much easier to handle.  Once i had my heart set on acquiring one, i sold off some of my lesser-used cameras in my collection, like my Nikon S2 and my Bronica ETRSi. I still love the ETRSi with its light camera body weight and ease of handling, but I loved the 6x7 format so much.  I found an awesome Pentax 6x7 up for auction on eBay that had a TTL-metered prism, and it was also modified to let you shoot multiple exposures. The seller even threw in 80 rolls of Velvia slide film! So this beautiful Pentax 6x7 sits on the same shelf as the RB67 and the GX680 and is probably the heaviest camera shelf known to mankind, currently dubbed "The Heavyweight Class".