Mike,
It appears that MANY have produced some serious numbers with MSD's products. I won't argue with MSD's success. I have also personally witnessed several MSD failures... stock replacement and otherwise. Hence, MSD products aren't allowed in my shop
Electromotive is probably my biggest competitor (I'm a Wolf3D distributor). Even still, you'd be much more likely to find Electromotive on my car than MSD. If you're just looking for DIS, look into their products.
On the other hand, If you want the full-meal-deal ie, a complete engine mangement system, then Wolf is my first choice.
SDS is good stuff as well. It does limit growth to some degree and its similarly priced with Wolf.
MS is very versatile and inexpensive, but does require patience.