After 61 years of rescuing cats (with a high of 13 at one time) I've had to stop due to old age--can't move fast enough any more. Those decades of experience say I ought to know by now which piller is the best--and it's this one!
Our older cat needs 7.5 mg methimazole twice a day and half a large seizure drug every eight hours. The 5mg size meth, when cut in half to produce the extra 2.5, leaves two sharp "corners." The seizure drug has to be cut in half again to produce a manageable size, also leaving more sharp corners. But the secret of successful pilling when you have to chop up the meds is to put the appropriate amount into a capsule blank and then into the piller. Ask your vet or pharmacist if he or she would let you have some blanks to try for your pet. You'll learn which size is best for your pet and how to fill the capsule. "Vegetarian" caps are also available--see Amazon for all types. (Or perhaps Revival might be talked into carrying blanks!)
I make up a batch of loaded capsules once a week. The one thing to watch for is if your piller is still a bit damp from cleaning after a previous pilling, don't put the capsule into it until you're ready to go, otherwise you end up with a gummy, dissolving capsule stuck to the piller and your pet trying to swallow (or spit out) sharp pieces. It's a bit tedious to make up the capsules but it's a genuine lifesaver if you're dealing with feral or semi-ferals. Oh, and have a nutritious treat ready immediately after pilling. After a week of pilling and treats the pet will be much more compliant and your hands will be free of scratches.