I don't know if any particular sound I heard is characteristic of meshplates, but, the sound of EML's solid plate 2a3 is much more like other 2a3's--very tight, dynamic, slightly lean and punchy sounding. I own very dynamic sounding speakers so I didn't mind the less tight sound of the meshplate tube and I did like that wash of sound that evelopes the listener that I got with the meshplates. I used the description "phasey" because the sound is a littlbe bit like when speakers are out of phase, but, instrument locations remain solid and correctly placed; in other words, it is a rough description. As I said before, I like the meshplate tube in my Kageki amp.
I like very much the sound of several OTL amps I've heard. The immediacy, and liveliness of good OTL's are something everyone should at least experience. Speakers come alive with OTL's. Like any type of amps, there are considerable variations in the sound, from different choice of tubes, components, design, voicing, etc. Unfortunately, there are not that many commercial choices out there. The amps I particularly like are custom-made ones that utilize a television sweep tube.