Moon i1 I.5 220i 250i 240i 330A differences?

I want to buy a used moon integrated. I am looking for a bright, immediate Fast and open sounding integrated or power amp that will energize warm rounded speakers 89db 5.8 to 60 ohm.
the internals of 250i and i1, 220i and I.5 look exactly the same but I have read somewhere that the newer neo series 220/250 sounds brighter. In both cases I am concerned that these Amps might have reliability issues as they do not have cooling fins. 240i and 330a do.

I am looking at a Sugden a21se (single ended class a) too. 
Do the 50w (250i/I1) vs 40w (220i/I.5) even make a difference with my Easy to drive speakers ?
In the last 2 weeks I’ve demo’d the SimAudio 340iDPX driving my Harbeth M30.1’s & the Hegel H590 driving Harbeth M40.2’s & would recommend the Hegel for warmish speakers..I think Pure Class A & a warm speaker will sound a lot like the old Conrad Johnson tube stuff,a bit too sugary.The Hegel also had better headphone performance...
I just replaced my Vincent SV-237 with a Simaudio 600i.  I was disappointed when I first heard the 600i because it lacked some of those qualities you describe, which the Vincent has in spades.  Except for maybe the "bright" part.  I wouldn't call it that, but there is a lot of energy in the upper mids and treble and it's very responsive to tube rolling. 

After some extended listening, I do like the 600i better, it's more refined, easier to listen to, and a little more detailed.  Speakers are Harbeth P3ESR. 

Jump on a used Vincent if you can find one.  First 10 watts are Class A, 150 watts at 8 ohms, 250 at 4 ohms, and a tubed preamp.