To actually state my opinion, the monk is clearly better. The Expert can pull of skill optimization more easily than the Monk, so it does have an edge. But the Monk can accomplish all the same effects, and it gets enough skill points that it doesn't have to dump valuable points into Int (as a Fighter would to get access to the 3 Abusable Skills, for instance; an Expert, obviously, doesn't have to either), so it's not really a point against the Monk. Yes, ranks in Handle Animal and UMD are cross-class barring some trick to nab them as class skills (do we have a handbook on this, by the way? I feel like there are bound to be ways of getting them). Presumably, if these abilities are worth being an Expert to get, then getting them and still having all good saves and some class features (however terrible) is, strictly speaking, better.
Handle Animal has fixed DCs that are trivial to make for the broken uses. UMD has fixed DCs that are slightly less trivial, but still not difficult. By level 10, neither of them should fail either Handle Animal or UMD checks, ever. Diplomacy is harder to get to the point where you cannot fail the best check (you need a +49), but do you really think the +4 synergy bonuses are going to be that big a deal? If they are, the monk can afford to dump the 20 skill points into those skills by the time those numbers are realistic anyway. It already has Diplomacy as a class skill, so this is really all it lacks in the Diplomancer arena (and it does have easier entry into Tattooed Monk as a Diplomancer staple, which is at least something to be considered, if not a solid point on its own).
So, basically, the Expert can be more effective through skill abuse at lower levels, but the Monk does at least have class features. Skill abuse probably does let the Expert win, though, because of UMD with consumables and Handle Animal shenanigans, but I would expect the Monk to be capable of similar shenanigans by level 6 or 7 in at least one of the important skills that it doesn't have as a class skill by default. By the time the Monk has caught up to the Expert in ability to meet these DCs, being a Monk is strictly better.