Haven't used a Magnetospeed.
The only ones I had & used was the ProChrono, Oehler Mod43 PBL, and the Chrony.
One time I set up all three and shot through them at the same time.
Results were surprisingly similar and only differed by 20fps ES.
IMO, what my experience yielded was that one brand would stumble up this type of light and another stumble under another type of light. While all worked well under bright overcast light. The Oehler didn't like bright sunny light, while the Prochrono did. The Chrony seemed the most tolerant, but because of the hinged design the angle of the optic sensors varied a bit each time I set it up resulting a little more head scratching than I would prefer. So make sure your consistent there. Of the three the Oehler was the one I settled on, even through it seems picky about it's light preference. When I get really anal about things like Velocity ES & SD I set the screens up on a 10ft pole w/ 5ft spacing on screen 1&2 and 10ft spacing on screens 1&3.
One thing I liked about the ProChrono was it's ease of setup and use. After we had it's offset from the Oehler figured out, we'd set it up down range infront of our target to capture down range velocity in order to do a V1 V2 BC calculation to fine tune our actual BC. You could read the display w/ a spotter at moderate ranges, at longer ranges we had to use a person w/ a radio. I always dreamed of having the acoustical target for the Oehler PBL but never could justify the cost. I do have the strain gage setup for it though, and getting pressure data taught me a lot.
Hunt'nFish