I have used the lsm one that is intended for doing the springs on the motor both on and off the motor with success. If Im doing them off the motor I just let the tool open the valve slightly then give it a little tap with a dead blow to release the keepers.

Changing springs right now on the engine, this Moroso works but it’s a pain in the butt. Might have to order something else for next time.

I have the LSM on head ones for my stuff, best setup I've ever used. Getting the LSM one for heads off now. I've been using a ProForm and it works, but is a little awkward and starting to bend in the middle of the frame. The LSM is expensive, but one damned nice tool. Definitely worth the investment

Wife asked what I want for Christmas. LSM tool was first on the list.

Just pulled two springs off my engine today with the LSM tool, makes it sooooo damn easy!

I have the LSM for one set of heads. But I just got the Buxton for my new engine. I like the Buxton better because the adapters are are cheaper to buy for different heads. I bought the valve spring tester that goes on the tool. It is all a very high quality piece.

A friend recommended the Buxton but man, they are sure proud of it.