I have never noticed any latency. I blame the manufacturer-specific Android "improvements", as I use plain AOSP and don't have any trouble.
My EVO 4G gets about 24 hours battery life, with moderate usage during the day. (But again, this is because I don't use HTC's build. With their build, the battery life is barely long enough to boot the phone.)
I've used vanilla Froyo on the Nexus One. It's dog slow. I don't think this problem is isolated to OEM-specific Android modifications (though they certainly don't help).
Responsiveness and framerate-wise, even a simple cursory examination will tell you: WP7 and iOS run laps around poor old Android. I got to play with a Nexus S recently, and the responsiveness is greatly improved over Froyo on N1... but is still noticeably less smooth than either Apple or MS's platforms.
It's an odd day when MS's UX is more polished than somebody else's...
One area where Android's lacklustre performance really hurts usability is diving into menus. iPhone came up with the novel idea of sliding menus - a simple animation that communicates a lot of context to the user (A belongs under B triggers modal window C, all based solely on the direction of the swipe animation). On Froyo+N1 this animation is jerky enough, frequently enough, that this relationship can easily be missed, resulting in more user confusion and worse UI comprehension overall.
Google needs to realize that we are in the year 2011, not 1995. "UI design" is no longer about placing the right buttons in the right places, and animation is often now the defining line between an easily comprehensible user experience and an obtuse one. IMHO graphics/animation performance is the #1 obstacle in Android's way, and the main advantage everyone else seems to have on it (and it's a huge advantage).
When I use a 2.2 phone, my impression is one of annoyance. I don't know if my touches will be detected, and even if they are, I don't know how long I'll have to wait for the phone to respond. Heck, I enjoy using WP7 phones more than Android because of the performance, despite the fact that WP7 is significantly less featureful than Android! Navigating WP7 is a pleasure, and it never feels like the phone stands in your way. I have yet to get this feeling from Android.
How about we compare the N1 (released Jan 5th, 2010) with the first gen iPhone (released June 29th, 2007)? Even the 2007 iPhone had smooth scrolling/compositing/animation and was always responsive to touch gestures. I'm pretty sure you can't claim a phone made three years before the N1 had an unfair technology advantage, right?
It's interesting how you railed on people earlier for mentioning that responsiveness and animations weren't great, and yet you have animations turned off.
I have a Droid Incredible. (Similar specs to the Nexus One)
I don't have animations off. I have 5 home screens and 3 active home screen widgets (Beautiful Widgets and 2 different Jorte Calendar widgets.)
I don't have any problems with responsiveness or battery life.
I have a DI as well (with an undervolt/overclock kernel) and while the stutters are quite short, they're definitely there. As an easy example, scrub left/right quickly using the optical joystick on the stock home screen. If you're looking for it or paying attention, it's not that difficult to notice 2-3 frame pauses elsewhere but those are intermittent so I assume they're GC pauses. It doesn't hinder my enjoyment of the platform, but when you're looking for something to criticize it's an easy target.
As for battery life, it depends entirely on where you live. I experimented on it for months before finally figuring out that well over 50% of the power draw on the system is the data network (mobile network option when you hold down power). If you have it on when you have really weak/no reception, the phone will burn through the full battery in about 4 hours and it's pretty simple to lose 20% battery in 15 minutes. If you always have a decent connection, your battery life will be fine, if you happen to live in a place where you have holes in your coverage (e.g. NYC urban canyons), battery life is terrible.
After realizing that, I set up a set of Locale rules to shut down the network when I'm on the wireless network at home/work and to shut it down when I lose signal. Combined with the undervolted kernel, I normally get 48 hours on a charge for my normal use (~350MB/mo).
For perspective, the first-gen iPhone and iPod touch are perfectly responsive, even though they're ancient in gadget years. When there are Android phones which feel as slow as crud despite featuring the same (or better) hardware as an iPhone 3GS, you have a big problem.
Google has done a lot of cool stuff for developers in the last few iterations of Android. The NDK has evolved into something quite decent, definitely good enough for writing games now. But responsiveness is the major user experience issue that they've completely failed to address.
My EVO 4G gets about 24 hours battery life, with moderate usage during the day. (But again, this is because I don't use HTC's build. With their build, the battery life is barely long enough to boot the phone.)