I have been an Eagle user since 1998. After they were bought by Newark, I was extremely disappointed with what they considered updates to the package. For the first time ever, I experienced a series of crashes. And it doesn't stop there. The routing features didn't improve much and transparency didn't work well enough for me. Basically, there weren't enough usable updates that has compelled me to continue using it.
I switched to Altium in 2009 and part of 2010 just to finish up an audio amp, but then happily left after dealing with its constant DXP.exe and "Access Violation" errors. I made some very nice looking and performing PCBs with it, so it wasn't a total loss.
I am about to embark on to DIPTRACE. I've watched the videos and some of its GUI in the ERC/DRC, particularly, seems remarkably like Altium. I am interested in its import/export abilities as I have scores of designs in Eagle.