Having had some time to exercise the case+holster, car mount and extended-life battery (yep, I gave in) for my HTC Droid Incredible, I am now prepared to render my verdicts.
First up: Seidio Innocase II Surface case + holster combo
Seidio remains one of my favorite mobile accessory brands. The Innocase II Surface is perfect -- light, great fit, great protection for everything but screen, (LOVE the camera lens protection!) and even with the case on, not too much bulk for my pockets, no pants dragging at the waistline due to weight. As such, I've had no reason to use the holster, which was an unwanted but pragmatic requirement since the days of my brick of a HTC Hermes some five years ago.
Two thumps up! Three if I had a ... three!
Next up: Arkon universal car mount
I had hoped to use the Arkon in a vent-mount configuration, but in my 2001 Blazer, that's a no-go. I'm not sure if it is the Blazer's vents, the Arkon's vent clips, or a combination of the two, but this is just not a sturdy setup. I have not had a chance to try the suction cup, I'm not sure I really have a convenient area for it, but will try soon and report back. All in all, not thrilled with Arkon. The part that holds the smartphone is snug, I do like that, but the rest of the kit seems flimsy.
No thumbs up at this time.
Finally: Seidio Extended Life 1750mA battery
Back to Seidio! I decided to trust the brand and cough up the cash for the 1750mA battery, 400mA more than the standard battery provided for the Incredible by HTC. Not the beefiest extended life smartphone battery out there, but I did not want to disturb the Incredible's awesome sexy slim & convenient profile, especially not with the Innocase II Surface in place. I wasn't sure this was going to be worth it. I'm still not certain it was. I haven't run out of juice in the middle of the day since I swapped in the extended life battery, but that could be better battery management and charging practices (screw USB!) on my part as well.
I'm going with one thumbs up on this one. I think I'm seeing increased battery life, but it could be wishful thinking as well. It has not been a total disappointment, but I'd rather have spent $20 on it than the $59 I seem to recall dropping.