First things first: the i-mate SP5 is awesome. I'm really impressed.
I told myself I wasn't going to write anything up due to time constraints, but I've received a fairly steady stream of e-mail asking for my thoughts and now I feel compelled to say something. I'm just going to do a quick run-through of some of the things I've noticed after using it for a week.
It feels as solid, if not more so, than the i-mate SP3i, which, at that time, was the most well-built phone I'd ever used. It feels slightly larger than the SP3i, but not much.
The joystick now has a little rubber piece in the middle of it which makes it a bit easier to control — it (and the OS) are very responsive.
The screen is breathtaking. It's got a very large DPI due to the fact that it's squeezing 320x240 pixels into a 2.2 inch space. It's almost impossible to make out individual pixels (and I tried really, really hard). While obviously great for looking at photos, the screen really shines when browsing websites — tiny type is infinitely more readable than on past devices I've had (and, incidentally, Gmail Mobile is perfect on it; more on that in another post).
Getting the WiFi setup was mindless and it works really, really well; I've used it on three separate networks and have had no trouble at all. Much to my delight (and surprise quite frankly), data connections default to WiFi first and then fall back on EDGE if that fails (assuming you set it up that way). Very nice. This is obviously how it should work, but I wasn't holding my breath. There's also a feature that will alert you to the fact that a WiFi network has been found, which could come in pretty handy.
I recommend getting a copy of Total Commander and really pushing the WiFi with its FTP client — I think you'll be amazed at the data rates it can sustain.
Like the SP3i, the T9 implementation is fantastic and has actually been improved a bit. The keypad is a dream to type on (probably the best I've ever used actually) and the fact that I can control the delay between key taps when I'm not using T9 is great (you can set it as low as half a second).
To be honest, I haven't used this very much, but the results of the pictures I have taken are about what you'd expect from a 1.3MP sensor, though they are a world away from the pics I could get with the Sony Ericsson K750i.
To be perfectly honest, I think my only real gripe with the phone itself (separate from Windows Mobile 5.0 Smartphone Edition) is that it's a bit "slippery"; I think that if the plastic was a little more rough, the phone would stick to your hand better. It's a minor complaint and likely something that won't affect most people.
I'm a little disappointed with the Bluetooth implementation. I can't send to the phone from my PowerBook (though I can send from the phone) — I'll likely be able to hack up a solution to this, but I haven't yet had a chance to try.
In summation, if you have the money and want a phone at the top of its class, then you need look no further than SP5. Like I said before, I don't see myself flipping this until the Nokia E61 comes out (and maybe not even then).