My phone dialer lag was so bad I was about to throw my Eris out the window. The other day I bit the bullet and rooted to xtrsense 3.1
beta test xtrSENSE4.0! [ROM] [8/12/2010] xtrSENSE3.1 [apps2sd,jit,oc]- HTC Sense - xda-developers
using the universal root for dummies:
Universal Eris Root for Dummies! - Android Forums
If you want to basically get your same phone with senseUI, very stable, brain-dead simple instructions, this is the way to go. I read a lot, and I think this is by far the best path to victory.
It is literally like getting a new phone. Everything actually works. No lag. Free wifi tethering. Overclocking if you want to, which is also simple. In fact most people use overclock to also UNDERclock (when the screen is off, or the battery is low, or the temp is high), and you actually gain battery life.
I considered my Eris a complete piece of crap -- it was unusable as a phone. And now I'm completely happy with it.