Hey,
Would have to say get the 100 without a doubt. I've found that in 50 watt mode it isn't much louder at all, and I personally think the 6L6's sound much better than the 84's at quiet levels. I get a much sweeter tone than I did with the 45 at really quiet volumes.
The graphic EQ is the 2nd biggest reason I wouldnt go back to the 45. It is godly. It makes what is already a TRUE 3 channel amp into somewhat of a 6 channel amp. I can get my lead tones for channel 2 and 3 setup nicely then engage the graphic for some seriously chunky heavy rhythm sounds. While still having 2 independent clean sounds.
I wouldn't let the fact that its a 45 watt scare you into thinking its quieter. My 45 in extreme mode shook the the earth just as much as the 100 has in its 100 watt mode. I dont think i'll ever have needed even the 45 watt to near its maximum volume.
My other guitarist in my band also plays a
mesa nomad and he infact has the 45 model still. So I get to hear and play his all the time and I can make a sensible judgment that while tonally they are the same the added features and IMO better valves in the 100 make it worth the extra.
At the end of the day either way you're gonna get the most versatile, best sounding amp around at a steal. Geezus! If I could only get a price like that on one here...let me work it out/ 550 USD....thats umm £300 holy $hit i'm laughing its so fricken sad..my rhythm guitarist bought his used 1x12 nomad off **** in the UK for $1400 USD and that was a good price.
No wonder our country is referred to as the "golden island" by everywhere else...they can charge more for **** and us dumbasses still buy it