I have a Saga cutter that is the same as a Titan 3. Titan's are actually just re-branded Saga cutters. I also have a veteran sign-making friend who has a Mimaki. That said, Mimaki is a top of the line, very solid brand. My "Titan" hasn't given me any problems thus far, after 3 years of heavy use. My firend's Mimaki has tangential cutting, which is a big deal. It actually picks the blade up and rotates it to give very clean corners. Not sure which model of Mimaki you are looking at, but I would find out if this particular cutter has that feature. Very small details are no problem for the Mimaki. The Saga/Titan has worked well for me, and I really haven't had any problems other than dull blades, and having to reset the offset once or twice.
My main concern would be what software works with each cutter, and if you are comfortable with it. I had an older cutter with SCALP, and it was frustrating. When I got this newer cutter, it came with a re-branded version of VinylMaster Pro. I love it. I can do 90% of all my designing and tweaking in it, without opening up Adobe softwares.
I'm sure you will be ecstatic with any servo cutter after using that SC. Whichever you choose, you will just have to adjust to it, and get a feel for it. Just get a new, good blade (Clean Cut), and start learning all the features and quirks.