I've got a lot of Lensbaby stuff, and love it all (I've put some examples of mine in the thread that M_Max linked).
I started off with the Double Glass Muse, all the examples there I took with that. I've since got the 0.42x UWA adapter, then the single glass, plastic, and just recently the pinhole/zone plate (all off ebay, if you're patient you can get them for $5-10 each, don't pay $50 in a shop). I later got a Control Freak, 0.4x wide, 1.6x tele, +4 & +10 macro, and creative aperture kit off ebay, for about 3/4 the price of just the control freak in a shop.
The effect isn't for everybody, and isn't for every shot, just like Fisheye it can get old quickly. When I go to process some photos, after a while I get sick of looking at them and give up. But I do go back to them, and I like the fact that they're "not just another boring landscape" and "not just another boring portrait". They have character, personality, individuality. Maybe i'm a 'purist' in that I don't PP much (except colours/WB, and the occasional background-blurring of birds), but if you're handy in photoshop, by all means try doing it that way too.
And lensbaby is not a tilt-shift, they may give similar effects, but totally different images. Lensbaby blurs the image border, it draws your eye to the subject. Tilt can either blur the top/bottom, or left/right of the image, never all at once, because it changes the plane of focus. Tilt can also give you seemingly infinite focus if you line it all up properly. Both take a lot of practise to get right, it all depends how much time you're willing to put in.
(and to try out a cheap tilt lens, I've also got a Pentacon-Six to EF tilt adapter, $100 off ebay, and a lot of Pentacon Six lenses, the best widest-angle is the Zeiss Flektogon 50mm f/4.0, pay maybe $100 again, $200 is a lot cheaper than a TS-E 45mm)
I have the lensbaby composer pro with sweet 35 too and agree with all of this too you definately cant compare it to a tilt shift lens.
its a fun lens to use at the widest aperture of f2.5 it is quite soft, not too bad but not great, however the in focus area at this aperture is too small imo as well.
also the FEEL of the depth of field at f2.5 on this lens feels alot more narrow that 2.5 on a conventional lens
i would put it more like feeling like 1.4 or 1.2 DoF. Wide open all you really get is massive amount of blur and very little in focus. of course its also all releative to how close to you subject you are too.
So I prefer to stop it down to f4 or f5.6 and around here its sharp the oof blur is super smooth as it has 12 circular blade aperture even at f4 or 5.6 the oof blur goes to mush very quickly.
It takes some practice to use but is fun for creative stuff.
no AF confirm chip is annoying for the price they should have put this on
Build quality is good though on the sweet 35 and composer pro. perhaps it is a bit overpriced