The big one, not the mini.
I've never liked the channel layout (with Mark-IV, the mode I'd use for leads, falling on the same channel as IIC+ and Extreme, which is the mode I'd be using for rhythms). But, 99% of my distorted lead playing on my Roadster is done on Ch 3 Vintage, my "lead" sound, and if I was gigging I would probably just use one all-around distortion sound for leads and rhythms and just use the lead boost to take solos. So, really, I'm kind of being silly here.
And, I've always LOVED the Mark lead sound. My Roadster gets damned close... but the temptation is growing. I probably wouldn't keep both, and I REALLY like the Roadster. It's also the longest I've owned any amp, I think, so I feel guity that I'm even thinking about this, and part of me kind of LIKES the fact I'm using a Recto for sounds not normally associated with a Recto.
There's a good reason:
It's a Mark V.