Will be a long wait since I just installed the NOS one.......... my past experience with retipping was when I had a Troika, bent stylus then had it redone at Expert Stylus (forever wait). But they did a great job and cartridge sounded excellent. Loved it.
You buy a used cartridge eventually you are going to face re-tip or buy another or upgrade decision.
The monster is an absolute stunner on the Linn/Ekos. I had a genesis 1000 when they first cane out and that too was phenomenal. My diamond came off the cantilever. go for the retip. The comment as being available, How lucky are you? You may or may not get lucky. Nothing a day ago on Hi-Fi Shark and I am always looking. So you have competition. Kept checking for a long time before the one 2000 came up-the retip. I hit buy it now.
I have a damaged Troika that came with my table- its at Soundsmith now for a rebuild. So I am a proponent of rebuilds. There is someone on ebay advertises can rebuild Monster but no experience.
if you dont like it when it comes back you should be able to sell it.