Kody, the ruggedized Bosches, like Technobots sells them are just the best power/weight to pricetag ratio.

Thats the main reason so many people use them.
To go for a stronger motor ,like the Mag will increase the total pricetag enormously.As you need stronger speedos, and more batterypower.

In other words, it all depends on budget.

At the moment I still use SLA batteries, and not even the most expensive ones either, because I do not need to buy the more expensive NiCD batteries and matched chargers for them.