Having used both, and if money didn't mattered, go with the Martin.
Firstly, the Martin is brighter, it's 5000 output lumens. The Design Spot measured roughly 3,800 lumens. Even though they use the same lamp, the martin has a superior optical/reflector system.
Another is speed, the martin wins again.
The wash is almost pathetic in my opinion. I refuse to use it because it looks like someone put wax paper in front of the lens. Lights up the haze onstage like our cyc lights would.
And lastly.. LASTLY.. in the middle of our show, out of our four design spots, one of them suddenly started showing the "error" code on the onboard LCD. It would do all sorts of erratic things. The prizm effect would randomly come in and out for a half second. In one of the scenes, all of the design spots spin in unison from stageright to stageleft. The one troubled unit lagged behind by 20 or so degrees. During intermission we scrambled, and after the show ended, we decided to use our old, but trusty technobeams for the remaining shows.
Currently that unit is going to be shipped to LA for elation to service. It's only 6 months old and its seen less than 500 hours. Oddly, I was able to compare a Technobeam and a Design Spot side by side. The Technobeam is a good 30% brighter when both are are on their no gobo, no color position. Not bad for a decade+ light. The Technobeam is rated at 4,000 lumens. Makes me wonder about the output on the Design Spots.