I will not dwell on the well-known statements "5 times faster!", "Full flash!", Etc. I will tell you about the little things that I noticed after 10 hours of use.
Added a native Russian keyboard, the language is swapped by a space, the three-line layout (not counting the lines with a space and controls), “” is absent, alternative characters can be entered by holding the button (like on Smart keyboard and HTC keyboard)
A strip indicator appeared in the camera with quick access to the settings (the sidebar with the settings used to get out)
In contacts, the scrollbar began to scroll by Russian letters, this was very lacking in 2.1 and was solved only by third-party programs / firmware
My favorite Seesmic twitter client stopped connecting (the problem was solved by deleting the account settings and creating anew with the “use secure connection” option disabled).
Twitter's native client is now built into the firmware.
No applications can yet be transferred to the SD card (for transfer, it is necessary that developers include this option in their applications
With flash, some sites have become noticeably slower to scroll (a flash is placed from the market, or it is clicked on any flash item in the browser), it is possible to set the flash to turn on when clicking on an item, but it does not help much if the site is overloaded with a flash
During use, the browser has crashed 6 times, which has never happened at 2.1, which is difficult to say. in 3 cases the flash was disabled
The yxflash player does not work, the only player that at least played avi files on the Nexus One, at the moment it cannot be found on the market with firmware 2.2
The SMS Unread Count application does not work, according to other users, most applications working with SMS also refuse to work
SMS and GoogleTalk applications are now in a light gamut, which is somewhat unusual, it seems that there is no possibility to choose an old dark skin (it looks rather strange because the contacts, etc. are dark, it violates the feeling of integrity and uniformity of the interface)
Gmail applications got the opportunity to use copy / paste, there are minor interface changes, the feel has become more pleasant.
The “sheet” with the list of all applications has slightly changed, the names of the applications are no longer cut off (at least those two-line ones that were previously cut off, I don’t have a single three-line name, some names from one word that were previously transferred to another line are now single-line), special effect the scrolling at the bottom stretched to infinity stretched a bit (it used to be similar to the upper part, now there are not two rows of icons, but four)
The trackball backlighting is now multicolored on a non-rudimentary phone (I noticed it when notice from twitdroid - blue)
So far this is all that has been noticed. I will update as new pros and cons find