If I want to run IC2 experimental, what do I need? A certain forge version? A certain library? I understand it is very unstable, I just would like to mess around with it.
Recommended : Latest forge and NEI (for spawning items -> testing purposes).
It will be playable, however it will be very broken, with missing functions, textures and exploding machines if you use your common sense about EU (The Energy Network is being reworked)
I was using experimental build 44 (been away for a week, now) and it works much better than the latest IC2_lf build (mainly fixed textures, also noticed changes in recepies).
We only tested the basic features and did not go into much detail or advanced features yet.
We did encouter explosions when you have circular energy lines, but thought this might be intentional and can be fixed by coloring the cables to keep them seperate.
Have critical new bugs been introduced in later experimental builds?
I was thinking of upgrading to a later build.
As long as you don't try using the newly added machines and not add too many energy-emitters to network you'll be fine.