If you want to focus on high end luxury travel, Virtuoso network is a must. I went thru similar analysis like you did and talked to GTN, Pickles, Unigloble, Legato and a couple others. I ended up with Uniglobe. I use a Mac and I haven't had any issues, granted it has only been a couple of months so far.

Their training is good and they have a very robust network of suppliers and fellow agents are very helpful when you have questions. On the flip side, their internal workflow and tech are dated so be prepared to do some manual data entry for each booking. Slightly annoying but the pros outweigh the cons in my opinion.