Ok, you're mentally going after this the wrong way. Forget rate of fire, pretend it doesn't exist. Go out there with a pump because you want to, not because you have to. I've always preached to shoot what matches YOU, pick a marker that fits your playstyle and that calls to you. Conform the game to how you play it, and if you're being drawn to a pump, then go with it.
Then there's the confidence side. Any of the old timers here who know me (and yes, it's me, even if I haven't posted here in 5 years or so and my account still says 'Newbie' from 2008), they know I'm not an arrogant prick. But I always walked on that field knowing I could dominate anybody out there. Not because I had the talent, or the equipment, but because I had already won the mental game. This gave me the freedom to do things that were, quite frankly, barkingly insane. The result was a tall guy playing absurdly aggressive with a stock class phantom, usually up on the point, and controlling the tempo of the game. So I'll tell you from experience that you can make it work, and it can work well beyond the local level too.
Now, for the technical side. No, you can't SHOOT as fast. But you're also not encumbered by the case of paint hanging off your lower back, a huge hopper and a bulky air tank. Those are the compromises and the weak points of playing an ROF game, it's heavy and bulky. What that means is you're able to move faster. You can twist your torso faster, you can snapshoot faster, you can swap sides in a bunker faster, and you can run faster too. Particularly if you go stock-class and dump another few pounds of gear.
There's also a myth that pump guns are more accurate. Well, forget that myth. Pump guns aren't more accurate, pump players just focus more on accuracy. When you've only got a stack of 10 every shot counts, so you naturally gravitate toward being more careful with your shots. You're subconsiously forcing yourself in that direction, and over time your accuracy develops to match. Then people notice that the 'pump guy' is hitting tiny little targets, and automatically blame the gun. As a caveat though, this works best if you stick to a single gun. Switch around a lot, and your accuracy suffers.
So yeah, go for it. I'll also give you one last reason that you should.
It's fun as hell, and that's the whole point, isn't it?