The only sport I still actively compete in is BJJ (kind of old slow at this stage of the game lol), but my background is Judo, Boxing, BJJ and Muay Thai. I'm 38. I've been training in one combat sport or another consistently for my entire life.
My viewpoint on it is this:
Over the years I've watched/participated/helped train for all of those sports. They each have their own little eccentricities and details that are challenging to master. That said, between boxing and Judo, I'm willing to bet that if I could clone a person so that the physical and mental traits were identical and drop one in a boxing gym and one in a Judo school (let's assume schools of roughly equivalent quality), the one in the boxing gym is going to reach the minimum level of effectiveness required for a MMA fight much faster than the one in the Judo school.
Between the fact that there are a ton of solo drills and exercises for boxing so that it can be more easily practiced when not in the gym (and thus when the student doesn't have access to a partner) and the fact that it doesn't require the level of tweaks and adaptation for MMA that Judo does, well, like I said, I think the boxing can be learned quicker and will be more applicable faster than the Judo will.
Again, just based on my own anecdotal experience, but I've often heard this backed up by other trainers as well.
The above statement is utter crap and is highly subjective but I think you will find there are more people that try boxing and cannot stick it out than Judo has.........
Utter crap is a bit much. lol Not sure why you're so offended. In terms of people sticking it out? That's equally subjective. The gym I train at has seen many more people stick with boxing than Judo for example. In fact "sticking it out" is a primary factor in why so many Judo schools are struggling. Most people don't stick it out. I think it's fair to say that it takes a special person to stick it out in either sport.
That said, the context of this discussion is someone who wants to train for MMA so "sticking it out" is assumed for either art. I mean the discussion of which art he should pick goes nowhere if the response is "you won't stick it out" ...
EDIT:
And mind you that my posts are all directed at what is needed to start fighting. I didn't say for example, that you would be a pro boxer in a year. You won't. But with the amount of time the OP says he has, he's gonna come out of that with likely only a small handful of throws that he can really reliably hit in a Judo match. That's in a JUDO match. Now they have to be adapted.
In the right gym he could actually come out of a year of boxing training with a well rounded set of basics that can serve as a decent foundation for the rest of his game. Since that was his question, it seemed like the best advice from my point of view.
