A place I worked for a bit only had the evolution ones. From what I recall they were okay, not up to the standards of a Fein.... Rotabroach ones have good slug ejection, but the gearboxes arn't that good on the smaller ones.
We have an evolution mag drill thats been in regular use for the last couple years in our workshop (Engineers workshop) - HOWEVER we got a large contract a few weeks ago that meant we had to purchase another 2 from our local supplier to meet the deadline - both within 2 days of use experienced problems with the on/off switch which rendered them out of action - to Evoltions credit they organised repairs/replacements at break neck speed - dont know if it was perhaps a duff batch or perhaps something to do with the damp/cold weather that affected the switch contacts