I can't help you with the speaker specs, but since you're buying an already designed, full rate production item in either case I would focus more on how it sounds to you if you can audition both. Given your wide range of musical genres I would say a proper audition with your bass and preferred amp would be the best way to decide if you can get what the sounds you want/need.
It's been a while since I heard that particular MB 410, but as I recall it was one of their better sounding cabs especially if you like a darker, deeper tone. However, all the MB stuff had a an okay kind of sound to me personally - it just didn't grab me as a must buy and then sell my other gear (Mesa, Bergantino, GK and Eden) type of deal. Please note that we're talking purely personal taste at this point, not quality or specs.
The GK Neo 410 I heard punched pretty hard with a very full bottom end and bit of sparkle up top without getting overly brittle. It also spoke nicely in the mid-range and I would say it could hold its own against some of the high end 410's out there. In my head, all that makes it a great value given its price point. I own GK Neo 112 II's and find the 12 inch loaded cabs to be my favorite in the GK Neo Line. It's not a 10, 12 or 15 thing for me, it's just the way GK seemed to have voiced the speakers/cabs with those particular speaker diameters.
At the end of the day, for my taste, if I were replacing my Mesa PH 410 with one of these two I would likely choose the GK. On the other hand, I have gravitated towards almost all 112 and 212 cabs and find I like them easily as much or more than my 410. I attribute this not to speaker diameter directly, but to the way companies seem to be voicing their cabs with 12 inch speakers. In fact I'm betting you'll find a number of players who when asked what their favorite 410 cab is will answer, a 212. YMMV! Good luck with your search.
