I just heard the Isis and loved it too. I have listened to the XLF in two different rooms that were all top of the line Boulder and DCS, but they didn't' connect with me. There are a few lines that I really have enjoyed recently. The new Proac line is awesome. Very sweet mids and highs. Not clean like VAndys, but an engaging speaker that I could own and be happy with for years. The Avalon line is great too, but distribution channels have dried up and the company doesn't seem to be what they used to be, so it would scare me off a bit. Dynaudio higher end speakers that I've heard are also pretty amazing. Very musical.
In the end, I just validated the fact that the VAndy line is clean, fast and has highly accurate bass in all their speakers. Those carbon tweeters make such an amazing difference from the mids up (My Treo's are the older ones and I wish I had the CT's, lol). I am able to emotionally connect with VAndys, Proacs, Dynaudio adn even the Rockports. Any speaker needs proper room and set up though. All too often I've been hearing speakers like Magico and Wilson's that I COULD like, but they have sounded so different with the same electronics in different shops or homes. I fully understand why folks love them like I love the other lines. I get it, but they just aren't for me. There are only a couple of higher end speakers I'd purchase if I had the money as my room is tricky. Vandersteen's Treo CT's on up are the way I'd go again. When they are set up with the Ayre Twenty gear or Boulder or Audio Research or Aesthetix (all the electronics I've listened to them with) they just do most everything correctly. I have even listened to the D'agastino line on a couple of speakers and they too sound ok, but I can't see why they cost so much other than an amazing case and his name. They don't open up like the aforementioned amps.
DCS and Empirical Audio have been the best DAC's I've listened to (I own the Empirical Audio OSDE/SE). When listening to the highest of end speakers I have heard amazing differences in DAC's to, but that's for another thread.