@curiousjim --
**KEF dealer disclaimer**
Just wanted to add a couple a quick things for your questions.... The Metas are not super troublesome with room setup. If you need to run them somewhat close to a wall, they will work (especially when utilizing port plugs if super close). Of course a little breathing room is generally a good thing with "most speakers", so if you can bring them out a bit into the room, certainly try it.
I don't really consider the Metas to be "bright" in sound. You can add tubes somewhere in the chain if you desire (one of my favorite combos here is a Rogue Cronus Mag with my Meta demos), but it's not necessary if you don't want to play around with tubes. There are plenty of great sounding solid state options that work well with the Metas.
As Mapman noted, due to their size, they do have some limitations to overall volume and large room size. But they really are fun speakers, and play well above their price point (IMHO).
Hope this helps!
Taylor
www.goldprintaudio.com