Some of your questions depend on if you're willing to unlock it or not.
It doesn't get slow when you install a lot of apps. You can use a task manager to keep an eye on what's running in the background.
I honestly never reboot it unless I'm flashing a new kernel, a new ROM, or I need to wipe cache (which is rarely).
For RAM, this is a big one for unlocking. As of now, the stock ROM doesn't support HIGHMEM in the kernel, so you can only access like 100MB. When you unlock and flash a different ROM you can get access to like 256MB. After a reboot, I'll have like 225MB free. After a few days I usually average about 170-190 free.
One downside (which doesn't affect me) is the multitouch has some issues when compared to the Droid Incredible and newer phones. Something about cross axis.
Otherwise, I love mine
EDIT: Another thing is that depending on the apps you install and how many, the storage for apps can go quickly. Installing some custom ROMs will let you do Apps2SD where you can partition a part of your SD card and install apps to it. I did a 1Gb partition, but I probably could have just done 512Mb.