[LeelandS]

There are many other threads discussing this matter, the forum search feature will most likely satisfy all your curiosity. Here is the general consensus in a nutshell (with a few modifications).

Mecanums are fine. Don't let anyone tell you otherwise. Mecanums get a bad rep around here for some reason I can't fathom. But Mecanum drive is fine. If a robot on Mecanums fails to perform, it is often because either the rest of the robot didn't live up to the needs for the game, or the team didn't invest enough time into developing the drive system, not because the wheels are cursed. Mecanum does require a fair bit of programming and tuning work to get everything right, but when used properly, they can create a wonderful and incredibly frustrating (for the other teams) drive system. At FLR, one of the lead scoring robots in the field was on Mecanum. They evaded defense like it wasn't there and became the first overall pick in the draft, cut off in the Semi-finals by some very well placed strategic defense. No, you won't be able to push a robot with a strong drive train, but if you're using Mecanum and your strategy is to push, your issues run deeper than the robot.

Swerve is fantastic. It's maneuverable, and it doesn't sacrifice the traction that Mecanum wheels give up. It's a very fancy drive train, allowing for multiple driving styles (see 1640 for a notable example) that allow for versatility in different situations. The issue is, Swerve really is every bit as difficult as its reputation lends to. There are no cutting corners on a good swerve drive; it requires a full development cycle that can span through multiple seasons before being considered ready to put on the field, and even then, without a refinement in design and manufacturing resources (see the Swerve development of 1640 and 1625) it will be heavy and costly. In the long run, the pay-off of Swerve seems to be very good. I haven't seen it through yet, but if you look at the teams who have spent time refining a Swerve drive and continuing to improve upon it... Well, they are generally teams most people are unhappy going up against. Teams like 16 and 1717 have become dominant in FRC, partly because their drive system is just better than all else's. It's a great drive system, and its benefits aren't insignificant, but if you really wan't it to play out well, you need to be ready to invest countless man hours and dollars into the project.

I think that more or less sums it up. It's 1AM, so my head is a little loopy, but this is more or less a general take on Mecanum vs Swerve. Mecanum good, but hard. Swerve better, but really hard. It's a personal team thing if it's worth it or not.