I just got around to reading some of my old sailing magazine and I found a used boat review of the Mac25 in the March 07 issue of soundings magazine. gives a lot of interesting information on the boat and Roger Macgregor.
I've owned 2 of them. They not bad. I liked the pop top. When it's up you have headroom in the cabin. Often they're stored with the keel not lowered onto the trailer and that puts a lot of strain on the boat and can warp things. Probably faster than a 26M but not as fast as a 26 classic.
I have a couple of V-24's and I think they are great boats . Yes a little cramped but I use it as my lake boat and take my M-26 camping. Neither of my boats have the pop top . The cockpit of the 24 is larger than the M-26
I don't really have a benchmark to judge the Mac 25, but I was singlehanding mine after work today and passed a Catalina 22 going out as it was headed in. It turned around and came after me and I slowly but surely left it in behind until they gave up and headed into the marina. Second time I've bested this particular Catalina 22. I am fairly certain we both had standard hank-on jibs, so I am sure I have more sail area, and 3 more feet of LOA.