Conrad Johnson Premier 350 ss vs Premier 140 tube

Anyone compare these two amps? I have an MF2500a and I am considering upgrading to one or the other. I am driving Thiel 3.6's and also considering a pair of 7.2's. So I need to look down the road a bit when making this decision; any thoughts? My pre-amp is a CJ Premier 16lsII with an SCD-1 front end and Audioquest Volcano and Anaconda interconnects.

Thanks in advance

Chuck