Woohoo. The good ol' analogue vs. digital argument.
I've used or heard lots of different equipment. This includes some of the Fostex digital stuff, Roland digital, and Tascam analogue (cassette and 1/4"). (I've also used Otari 2" analogue 24-track and Sony 24-track DASH recorders)
My opinion is basically this: GARBAGE IN, GARBAGE OUT. You can have the best equipment on earth, in the best studio, and nothing will make a crappy band sound good. you can also have the worst, hacked, jury-rigged equipment in existence, and a great band, and sell albums from it. Forget about the digital vs. analogue arguments.
Here are the real questions:
How much do you want to spend?
Does it have to be new?
How many tracks do you want/need to record at once?
How portable does it have to be?
What are you going to be mastering to?
and also
Where are you going to be using it?
The last one I added because the consideration comes up, with heavily mechanical units, of things like vibration, mechanical noise, and environmental concerns like rain and dust messing things up.
The first question is obvious what to think about.
The second.. would you settle for a used unit? You can save a lot of money by buying something that's a few years or even months old.
How many tracks.. Some people do all their recording by themselves, so 2 or 4 tracks at once is not just sufficient, it's overkill.
Others want to record an entire stage or band at once, so the more the better. In myt experience, this is one of the most important questions to ask, because if you're stuck with a 4-bus unit and you need an 8-bus, you'll just keep kicking yourself for it.
How portable? Why bother asking this now? It depends on how good a recording you want et al. There's a lot of really GOOD 1/4" equipment floating around the used markets, and if you don't mind its size, it sure sounds fantastic compared to either cassette or most portable digital stuff (okay, there's my real addition to the a/d argument).
Last question (these aren't in any particular order) is what are you mastering to.. if you're going to master to a cassette tape, forget about having any worries about the quality of your 'tracker. Likewise if you're mastering to a <$40 sound card on your computer.
If you've got a good sound card, or a 1/4" RTR, or a DAT, or anything reasonably good, then go ahead and worry.
Just remember that a well cared-for cassette with DBX will give results that sound pretty damned good for something recorded in a basement.
If you take care of what you're doing, and if you mix well enough, you can get great results from an analogue machine as easily as from a digital.
Oh yes, final concern. Make sure the mixer can do what you want it to. And if you don't know what you want it to do, then see if you can play with someone else's, so you can learn what all those knobs do.