First off, I love using older cameras regularly, and Rolleis are probably my favourites. So I'm biased towards them, OK?
That said, I agree with others that the Yashicas can produce very good image quality. There's no doubt about that. But there is also no doubt that Rollei is the standard against which all other TLRs are measured, and there are good reasons for this. Build quality and reliability are outstanding. Apart from occasional servicing, they can literally handle decades of use without failure. Whilst later 3.5 & 2.8 E & F Rolleiflex models are the glamour TLRs of the Rollei line up, many owners continue to use all types of 1940s vintage Rolleis (and even older ones sometimes) regularly, and I've seen stunning results produced with any of them. With the possible exception of the Rolleimagic models, there is probably no such thing as a "bad" Rollei TLR.
There is some justification for arguing that a Rolleicord is the most reliable TLR of all, by virtue of the fact that it is a simpler design than a Rolleiflex. (Not that a Rolleiflex is unreliable, by any means. But after decades of use, the adjustment of the film sensing rollers of the automatic film loading system that nearly all Rolleiflexes feature, which automatically detect the "bump" in the roll where the film emulsion begins, may need to be re-set.)
In contrast, all but the earliest Rolleicords feature automatic film spacing, and simply utilise two red dots the photographer uses to manually line up against the marker arrow on the film backing paper. The Rolleiflex film advance system is reliable, but the Rolleicord features simple knob wind and it has many less parts. It's a simpler camera all round, and this also means most Rolleicords are lighter than most Rolleiflex types. For travel use, or trekking, for instance, the Rolleicord would be the one to pack. A good Rolleicord really is a wonderful camera, and the 75mm f/3.5 Xenar lens fitted to them is excellent.
If you are on a budget, consider a V or Va model, or even a IV. As I've stated here before, I think the V is a high point, because it has a very useful self timer for tripod or hand held slower shutter speed use. You can set the timer to give you the full ten second delay, or just a couple of seconds to help you steady a longer exposure in your hands. If you've never used a TLR before you'd be surprised what you can get away with in regard to hand held slower shutter speed exposures.
The Va and Vb models are great, too, and both have a left side focus knob, unlike previous types, which had both film advance and focus knobs on the right. All operate fine, and whether the left or right side focus works better for you is very much a personal preference - I've used both, and couldn't find fault with either set up.
The Vb type in particular sells for more as it has a quick release viewfinder. You can mount a prism on these. And it is the newest and last model Rolleicord. It won't produce image quality any better than an equivalent multi coated V or Va though, so if you're on a budget, the earlier models offer better value, if a prism isn't a must have feature. In this respect I'm not so biased, because I own examples of the V, Va and Vb...they're all brilliant cameras.
Getting away from image quality to less easily defined aspects of ownership, I've never owned another camera of any type which attracts so much favourable comment as a Rollei. The public in general, and younger student types, in particular, just love them (but then, they're beautiful things, so why wouldn't you?).
Whilst this may seem to be a superficial viewpoint, in fact it can yield dividends on the street. Rather than imposing a barrier to casual photo opportunities, (which may be created by the presence of a large SLR, for instance), in my neck of the world at least, it seems to create them. Instead of repelling people, they are attracted to the beautiful old camera I carry, and are frequently happy to be photographed with it.
To be fair, in this day and age, walking around with a Yashica will probably get you noticed, too. I think any TLR would tend to stand out. But (and this is a personal opinion), they're not as beautiful as a Rollei, and, whilst this does not matter a whit to some users, there is something very rewarding about capturing images with an iconic camera that is a design high water mark. Stating the obvious, the Rollei TLR is the original design nearly all other manufacturers copied to some extent, and this certainly applies to the Yashicas.
I don't want to dismiss built in meters out of hand, I own quite a few older 35mm cameras with built in selenium meters and they can be useful sometimes, even more so, the CdS types. But as I tend to shoot either B&W or colour transparency, I invariably find myself carrying a hand held incident meter for more accurate results anyway, so for me, the inclusion of a built in meter is of no importance, and, no matter what you end up acquiring, I'd encourage you to procure a reliable hand held light meter.
Sorry for the long post. Hope it helps.
Regards,
Brett