Heres the same breakdown I gave someone else this morning...I am on Hermes CFW 3.41 and choose to stay mainly for discless compatibility and dongle support in case anything neat gets added. Just depends on whats most important to you.
Few things to consider:
3.55 - Can update new games (that require 3.50 and 3.55) without a hassle. Discless compatibility sucks, so if your blu ray laser dies so does your gameplay. Sony took away 3rd party controller support. No dongle option.
3.41 - Can play almost ALL games discless, so if blu ray laser dies you can still play games. Can still use a dongle. You will need to find modded eboot files for some of the newer games (not as hard as you'd think. Theyre everywhere). Still have 3rd party controller support.
NOTE for both - With 3.60 games we are all now in the same boat now. Both 3.41 and 3.55 users will have to wait to see what happens with 3.60 games.
Note if you go with Hermes 3.41 CFW, locate a copy of Hmanager which auto-loads the payload for you AND it is also the original manager to integrate the ability to play large files off of an external. Irismanager for 3.55 is simply a port of the original Hmanager. Both do the same just depends on what is more important to you with the CFW's.
As far as I know, my ps3 has never had an undetected error.