ICE needs to have a purpose to be good at anything.
Eli is an excellent piece of purely taxing ICE, since it typically costs 4 to break (or 3 now with paperclip) and only costs 3 to rez. This compares very favorably with Wall of Static, which for the same rez cost is only 2c to break. However, Eli is not a good piece of rush ICE, since he can be clicked through and does not force a gear check.
In RP, it is important for a lot of ICE to have subroutines you can't just ignore to install (as outermost ICE) on centrals. In this case, ETR ICE makes the RP ability a click tax, but if the runner has to choose between hitting Ichi, Crick, or DNA Tracker before making a run on a remote, the cost is much greater.
Best ICE: Sherlock 2.0
Best icebreaker: Mimic(+Datasucker)