I've been using the UC-33 for professional VJ gigs for about half a year, and used it non-professionally for about a year prior, just for audio mixing. (The UC-33 is the ver. A of the UC-33b which is the same mechanically.)
I've just replaced the UC-33 in my rig with a Novation Remote-SL, and would HIGHLY recommend the Remote-SL after just a few weeks of use.
I do NOT recommend the UC-33 for professional use. The construction and parts are not of the best quality, in my opinion, at least for heavy use. I would put the knobs and faders through a hectic workout, tweaking, spinning, and flipping them back and forth to manipulate effects. A few of the knobs and sliders that I knowingly used more than others began to feel different... loosening up. While I have not yet had a total failure with a control, I can most definitely feel them suffering from wear and tear.
So far, I can't honestly say I've put the Novation Remote-SL through the same continuous use, as I've only used it for a few weeks. However, the initial quality and construction is without a doubt superior to the UC-33. The features, especially the LCD panel and extent of template customization, are above and beyond the UC-33. We're talking a whole new level of control here.
One other problem I was having with the UC-33 is that the MIDI signal would be lost and the controller was not recognized by Modul8, at which time I'd have to unplug it and replug it (via USB). I suspect this might have been due to a faulty USB connection a the USB port on the UC-33, and perhaps a result of how I had it placed in my case. This became more frequent, and I'd lose control multiple times during a single gig, motivating me to go ahead with the Remote-SL upgrade I'd been considering.
I would have gotten the Remote-SL even sooner, had I not had such difficulty finding it at a retailer. I was travelling so much that it wasn't very convenient to mail order it, and I'd figure I'd grab one at a big-box music store on the road... no one has them in stock. Internet supplies seem adequate, so I don't think you'll have much trouble finding one online, but do make sure they have the item IN STOCK at THEIR warehouse (not "in stock at Novation"). Finally ordering one that was reportedly "in stock" it actually took a MONTH to arrive. (That retailer will never get my business again.) OK, sorry for the rant on stock supplies.
Bottom line, spend a couple bucks more and order a Novation Remote-SL NOW! The model equitable to the UC-33b is the Remote-SL Zero, but they have others with keyboards, which I did get for other purposes, so I consolidated multiple pieces of gear with the SL25. You could get replace both a UC-33 and Oxygen similarly.