The Eduard ones I've used are custom cut for their own kits and worked extremely well. You'd have to make sure you got the ones for your exact kit because there are subtle differences in the framing between manufacturers.
I've used some Montex ones only once. These were generic ones included in a Kagero book but they did not fit the model I was building. I can't say that this is indicative f their quality though. I like the material of the Montex ones more than the Eduard.
I've not used these more than once but suspect that, if you are careful in removing them and if no paint has gone underneath, you might get away with using them one or two more times. However, each time will lessen the chance of a good result as the bond will be reduced.