As a recent first-time buyer, I can sympathize with your question. I read a lot of the stuff on this board for a month or two, and it really helped get me more grounded in what the main brands are, and more importantly, what criteria I should focus on in deciding what to buy. Here's how I ended up making the decision:
1. figure out what we (wife and me) want in a hottub
Size? Shape? Jets/features? I think for us these three were the most important initially. Regardless of brand, you need to figure out what you're after first - and then assume that you'll be able to find something like it from each of four or five major brands. So...just go out and look at tubs. Find the dealers who are in your area and check them out. Most important thing, IMHO, is to first consider *how* you plan on using your tub.
That means - just you and wifey (or S.O.)? Or? Kids? neighbors? friends? massive naked hottub parties?
That alone will dictate a bunch of things: overall size/shape/depth, price, site prep costs (you pay for voltage and concrete by the foot, amp and area!).
Next, what do *you* like about tubbing? When you have used a hottub anytime in your life, did you go to the lounger chair and full jets? Or do you like marinating quietly with maybe just a few bubbles, sitting fairly upright? Do you like foot massage? Music? Quiet? Watching TV? (all are possible options, built in).
For us, we wet-tested the lounge chair type of seating and decided it didn't really interest us, so from then on we ruled out tubs (a lot of models) that featured loungers. Some people (a lot of people?) love them, so don't let that sway you - just be clear what you like.
I knew I wanted foot massage and neck massage jets; and I wasn't too concerned about how much power the jets had - I personally didn't like the jets that you could use to pressure wash the moss off your stonework.
Size - as much as I would have liked to hang on to my images of tubbing with six naked 20-year olds (it's a JOKE - lighten up...) the reality is my wife and I really envisioned just using it for us, and perhaps occassionally having another one-two other *close* friends join us. But even that would be rare. so...for us that meant we could look at the round and some of the smaller square tubs.
2. Brands. After reading through various posts on this forum, and visiting our local dealers, we concluded that:
a) there are quite a few reputable makers out there, many of which we had never heard of
b) four or five main brands kept coming up as the good ones in our area - they may be different in yours (I'm not going to mention them - you'll figure it out for yourself).
3. Site prep - don't wait too long to get your electric and pad done. And don't forget to budget for it - it can end up costing as much as your tub if you want to go for a really custom installation.
And this is now getting pretty rambling - so I'll leave it at that.