I would imagine that the vast majority of BMT tools are used for 45acp revolvers since there are more of those around than in other calibers that are set up for use with moon clips. I'd be interested to know why you don't like it for 45acp. I especially like mine for demooning the empties. I have no experience with the tool you use, but I long ago forgot how much I paid for the BMT tool.
The first time I saw a BMT mooner was at the 2014 USPSA Revolver nationals and it was for a 627. The BMT mooner for rimmed cartridge is somewhat different in function than the rimless version. I thought it was a pretty slick gadget and bought one when I got home.
While buying the 627 version I looked at the 625 version and although slick is not IMHO worth twice what my Deluxe Moonclip Tool is worth. The rimmed BMT version maintains control of the rounds/cases going into and out of the moonclips The rimless BMT version only does so when putting them on the moonclip. The removal system just lets them fall where they will.
When I get back from a match I typically have a bunch of partial moonclips to deal with. The 627 BMT mooner lets me spin them all off, extract the empties cases, drop in fresh loaded rounds into their places, and spin them all back on the moonclip without ever touching the rounds that were initial still live rounds on the partial moonclip. The BMT mooner for rimless cannot do this.
With my 625 moonclips I use the golf club handle to removed the spent cartridges from the partial moonclip. As each cartridge is removed it drops into the handle. The handle will hold 18 empty cases before I empty it into my brass bucket. The Deluxe moonclip tool has no problem adding cartridge to a partially loaded moonclip.
Again nothing wrong with the BMT for rimless I have just found a more efficient and cost effective system for the way I use my 625 moonclips.
ETA: to be more on topic. Unless you are buying it as hiking gun I would lean toward the 625 over the 325 and a five inch full under lug is the best choice IMHO unless your buying it for IDPA then go 4-inch full under lug.