Don't forget that "really soon", as regards the bucket, can still be years away. I've been using my 6-gal bucket steadily for a year and change now and it still works fine; there's not even any appreciable wear and tear. I expect it to keep incubating solid brews for a good long time.
It's not quite as simple as less expensive = disposable. Sometimes less expensive just means less expensive. Honestly I'd recommend a bucket over a carboy unless you've got an active preference for the aesthetics of a glass brewing vessel (because they sure do look classy, don't they?) and you're comfortable dealing with heavy, slippery, breakable objects.
True, a bucket can last for years and years. As I said, it all depends on how much focus you want to put into taking care of it, both during use and in storage. Just like I've seen people get 10 years of use out of a 12 dollar cordless drill (the time he spent monitoring the battery on the non-regulated charger to make sure it didn't get over-charged was worth WAY more than the price of a replacement).
I don't have the patience to be that anal about things. Nothing wrong with those who do, but it's just not how I'm wired. I think durability is something worth paying a little extra for. I like the fact that with my glass if I get some krausen crust I can feel comfortable digging into it with a carboy brush and not worrying about scratches.
Then again, I need more fermentor space, and buying that many carboys would stretch my budget a bit beyond comfort at the moment, so I'm also going to start fermenting in buckets, too.
But I will admit I prefer the aesthetics of the glass. I am "one of those".
Just saying that any of the options will work just fine. It's not really a question of beer quality. It's a question of (potential) longevity, ease of care, and, yes, aesthetics. Decide which factors are important to you, then buy accordingly within your budget.
(As for glass carboys being slippery, I've found that a towel takes care of that problem just fine. As would several other solutions.... Then again, I'm getting to that point where I'm just starting to feel the years creep up on me, so I'm actively looking for solutions that don't require carrying ANYTHING. I suspect I'll be buying lots of tubing in the years to come....
)