The not suited for tube amps comment was likely aimed at OTLs due to the extremely low impedance of the LCD-5
I'm not sure where this myth about LCDs and tube amps (OT or OTL) came from, but I have yet to hear a tube amp that didn't work well with most or all of them. Admittedly, I haven't tried all of them with every tube amp out there, but I've done a lot of listening to various setups in the last 5.5 years, and have always been pleasantly surprised by how compatible they are.
In my own listening tests recently, I found the real-world power requirements of LCD-5 to be similar to LCD-2. The low impedance is balanced by the low-ish sensitivity in all the setups we had available, and based on my tests, I'd comfortably say that any amp that can drive LCD-2s
should have no problem with LCD-5s.
LCD-5s should "play well" with most of the amps on our
recommended amp list-- in fact pretty much all of them that I tried sounded fine-- including the LTAs (which have
no output transformers), WOO, Pathos, Manley, Burson, Deckard, Chord, SPL, Weiss, and iFI. Even the Dragonfly Red performed well with some power/volume limitations; the DF Black was a bit underwhelming in overall loudness and dynamic peaks, but it still worked fine and got to the heart of the music.
To anyone who's concerned about power requirements, you probably don't need to be with most gear.