180° from my experience. Those cups are oversize and you need a pry bar to get them off the glass. Those magnets look like ___ on the outside of your (my) tank. If you like them so be it but I don't care for the look.
Also never had noise problems with the 400's. I use 2 of them in circulation mode but you know how that goes. I also have a dead silent AC110!
Wait..maybe it's because of all those years playing rock guitar!