I'm pretty much in "browse mode" with this mod at the moment, so I exploring everything in creative to look at the new biomes and such.
I've found that every time I return from the Nether, the computer hangs when loading the world and then crashes. This doesn't generate a crash report. It just dumps me back to the Technic client screen.
It also does this when I explore for a long time. If I point myself in a direction and start flying, say for about 15-20 minutes, the I will begin to notice a definite FPS drop until I will get to a point where I can see on the map where the next chunk isn't loading and then the game will stop completely and kick me out to the Technic client screen without generating a crash report.
My computer should have plenty of ram and graphics capabilty to handle everything this mod throws at it so I don't know what's going on. It seems to me like this problem is some kind of lag based crash but I can't figure out how to stop it. Reducing the graphics quality and my render distance didn't help either.