I think I can answer this. I listened to Schiit's whole line of solid state amps with my LCD-Xs from bottom to top at CanJam recently. They sound fantastically clear and dynamic, but dry dry and more dry compared to tubes. If you're going for accuracy as in what the artist intended you to hear then go for the Schiit. Tube amps sound just as detailed but can give a warmer, smoother, and sometimes full on liquid 3D sound that is flat out beautiful. They do this by inherently adding small amounts of even order harmonic distortions. Not the crackley harsh odd order distortions like if you crank crappy earbuds to the max on a phone, but basically inaudible rich and pleasing distortions that sound amazing. Kinda hard to explain, you gotta hear it.
Anyway, another advantage of tubes is you can change the sound signature to what you like. Solid state Schiit you're stuck with how it sounds out of the box like it or not. My advice would be to start with the WA7tp if you wanna try tubes. I switched from that amp to a WA22 recently, but kept the WA7 cuz it's that good. Also, swapping tubes for the WA7tp is relatively cheap. You can get that amp to sound more flat and accurate, wide and clean, or fully deep, lush, and liquid for $30-$150 per set of upgrade tubes. It's so cool. And it looks fantastic! Also, it is a known fact that even the guys at Woo advertise in their marketing, that the WA7tp and LCD-Xs are a marvelous pairing. You won't be disappointed. There's even an extensive tube swapping guide thread for the WA7 here on head-fi. Anyway, good luck! I'm excited to see what you decide!
Edit: Disadvantage of tubes is they don't last forever. I think most tubes are rated to last 5000-9000hrs from new or New Old Stock(NOS..older model tubes that have been sitting around somewhere for decades new and unused). That's a LOT of listening. Most people stock up on the ones they really like though. However, some of the absolute best sounding ones are a bit hard to come by, but not impossible and DEFINITELY worth it.