It's no big deal that my DMX Operator doesn't have a master fader(that just sounds nasty, doesn't it?). I've been living without that feature for so long, that really, having that function would probably just end up confusing me.
For the most part, right now since I've "discovered" programming, I'm more into scenes. With logical channel assignments and groupings, I can "emulate" a master fader position within a block of addresses. Having a channel just for dimming does make things a bit easier. I'd rather use 3 DMX channels to dial in my color, then a master dimming channel to control intensity. This way your colors should stay true while your intensity can then be adjusted.
But as far as a usable comparison, I'd have to compare the LED Par64 Pro units to a traditional Par64. That's what I'm familiar. I can't envision the Design LED 36 since I don't have one. I can easily obtain a Par64 fast if I had to, but I'm hoping to avoid that. But, let's say it's comparable to a bank of 3 Par38's running 150-watt bulbs, I'd be thrilled.
When I buy the Par64 LED Pros, I'm buying 2 T-bars and attaching 4 to each bar. If I had the funds, I'd buy 16 and be able to really light up a small stage properly from just 2 locations(8 fixtures on the T-bar), but that won't fit into an Arriba case that I'm aware of.