Which brand of 45 tubes do you use?

I never got to try genuine NOS tubes; at best, I could get my hands on old tubes that tested strong.  Most of the brands I heard, like the National Unions, sounded very good.  They also don't cost a fortune. 

I haven't tried EML 45's, but, I have owned their similar 2a3 tubes, both meshplate and solid plate and they are quite nice sounding tubes. The meshplates are quite different from any other 2a3's I've heard--more open, with the soundstage more enveloping, and a "dramatic" sound (I've heard this tube described as "technicolor."

I liked the meshplate even though it was a bit over the top.  I liked the wide open soundstage, but, if someone said the tube sounded "phasey," I wouldn't disagree.  I used it in a parallel single-ended amp (Audio Note Kageki) and it had a reasonable life span, although not the kind of life that vintage 2a3s seem to have if run conservatively.

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.   

I liked the Joule Electra OTL I heard.  It was a nice warm sounding amp that retained the explosive dynamics and immediacy of OTL's without sounding harsh or rough.  But, the particular amp I heard developed bad tube sockets that cause it to occasionally deliver extremely loud pops (a friend borrowed this amp from the dealer to use on his 105 db/w efficient system and he said the pop was as loud as discharging a shotgun indoors).  This problem was reported by others so it is something to be concerned about.

The Atmasphere OTL's are also nice sounding units, though a bit too lean sounding for my particular taste.  With high efficiency speakers they often are a bit noisy-buzz/hum.  Still, they are a must listen to amp because they might fit your taste and they certainly deliver the OTL goods.  I've heard other commercial OTL's from the past, and I liked the sound, but, they seemed to be often in need of repair. 

There is the unique Berning circuit amps, which are the subject of debate whether they are OTL's or not.  I've heard both the Berning models and the Linear Tube Audio models.  For my particular taste, they are a bit too lean sounding.