A couple of additional 10.5" capable decks to consider: Pioneer RT 909 and TEAC X1000. I have no personal experience with the Pioneer, and never see them come up for sale, but they seem to be common enough in the US and Europe. The TEAC X1000 is a very nice deck (but it doesn't do 15 ips), and reasonably easy to work inside, which given the nature of R2R and the age of the format, you're likely to have to do at some point. As mentioned by Doc B, machines don't usually come to you in perfect working condition and you're likely to have to learn how to do some maintenance yourself or find someone who can, which given the weight of tape decks and relative rarity of technicians is going to involve some trouble and expense.
You should probably join a tape forum, Tapeheads is an obvious one. It has the usual variation of members that you find on other highly specialist forums, which is to say there are some prickly personalities on there. And rather more, er, patriotism than I am comfortable with. But you can get extremely useful information on the full range of tape decks really, along with other audio equipment.
A couple of advantages of the Technics deck deck over the TEAC is that it is 15 ips, and it's not belt drive. If you buy a belt drive deck like the TEAC, it's likely you'll need to replace the installed belt right away, and periodically thereafter. It's not too difficult or expensive, but not doing it is more fun than doing it, and on certain tape decks the belt is not as easy to access. The Technics eliminates that problem.
If I was suggesting a deck to someone with a casual rather than hardcore interest in reel-to-reel, I'd say go for the Technics RS1500, the TEAC 1000 (I have read that the 2000 may not be a great idea), or the Pioneer RT909. (I also like the far older TEAC A-series). The first two seem to be endlessly available, which is a point in their favour. You don't really want a machine that has a frequent point of failure for which you can't easily get spare parts. This is occasionally the reason why certain machines or makers are deprecated; you're not looking only at the quality of decks as they were when reel-to-reel was cutting edge, but at how they can be expected to perform (and be maintained) today, 30 to 40 years after the fact.
I have nothing against the other makers/suppliers that Doc B suggests, other than cost and availability. None of those are affordable options for me and some of them are difficult to acquire where I live. I see Studers/Revox in battered condition at high cost, when they're available at all. Ampex I never see at all.
If you're really going to go with this, be prepared for some cost well above and beyond the base price of the deck, wherever you source it from. Look for example at the price of pinch rollers for your machine; at some point, often immediately after buying, you'll need to replace it/them (see Terry's Rubber Rollers website for an idea of prices). Tape's not cheap either, and how long it'll continue to be available is anyone's guess. Even ignoring the cost of tape, you're almost certainly going to put hundreds of dollars into any machine after you've bought it, if you actually keep it running. It's pretty hard to avoid.
