I use the vk-5i with the ph-3. Wonderful, warm sounding system. I think the vk-5i is actually in the league of the ARC ref1 sonically - I think it may sound a little better (they're different - you need to decide). I've owned both. I was unimpressed with the LS16 and LS12. It think adcom 750's put them to shame to be quite honest
I have heard that CAT's are a little finicky and very dependent on the tubes that you use with them.
I tried an AA 3A and didn't like it. More for ergonomics that anything else. No remote, and the volume steps are way too coarse. This may not matter to you. It sounded pretty good, but I think the BAT and upper shelf ARC stuff are the best I've heard.
A great preamp/phono combo you should look into is the vk-30SE w/phono stage. I borrowed one from a friend and was very impressed with it. Very transparent and quick.