It's not like you're going to rocket through the categories on a much different trajectory if you've got these versus any other wheels - no wheel is going to do that for you.
50s are fast. You've probably seen the wind tunnel stuff that we posted, which shows that there are quite a few watts of savings versus FSWs. So in your typical weekend stage race TT, for example, all else being equal "you on 50s" would beat "you on FSWs" by an accountable margin. "You on 50s" would not be quite as fast as "you on Rails," and depending on the wind conditions "you on Rails" and "you on 404s" would be sort of a toss up. That's not really the way I think about the benefit of aero wheels.
Think of a fast, downhill, 90* turn, which spits you out into a short rise and then a long roller section. The typical action at the turn is aggressive, with riders using the turn to try and initiate selection. I'll give you a few scenarios for how that turn can go:
1. You get stuck on a bad line, or behind someone who screws up the entry of the turn, and no matter what wheels you're on it's going to cost you some bullets to close down the gap to riders ahead of you.
2. The guy in front of you goes into the turn well, but then botches the second half of the turn.
2a. On bad wheels you can't correct your line and see (1) above
2b. On good non-aero wheels (FSW) you can correct your line and you're going to use a small number of bullets, same as most everyone else, to make the turn basically at par with the group.
2c. On good aero wheels, you correct your line, use a smaller number of bullets, and do the turn at par.
3. You go through the turn behind a guy who just freaking nails his line.
3a. On bad wheels, he gaps you and you shoot bullets to get back with him
3b. On good non-aero wheels, you follow his line and do a bit better than "at par" through the turn.
3c. On good aero wheels, you follow his line, float up the early part of the rise, come through the guy who led you through the turn, start pedaling, and now the two of you are off the front where you have the option of having a go from there, making the group work to catch back on, or coasting and finding a nice spot back in the field.
3c was my scenario on a recent group ride, and although it wasn't THE crux moment of that ride, I've no doubt that it helped set the stage for me to ride how I'd hoped to as the ride wore on. Everyone tries to think about aero wheels as having this very decisive impact, and I don't think they do. It's not like you go off the front and they are this magical tail wind that carries you to glory. If you ride smart and well, they can very effectively help you to avoid having to shoot bullets when it's not going to get you anything, and then have those bullets to use when they can actually do you some good at decisive points.
That's my treatise on what aero wheels do and don't do for you. In terms of our 50s versus others, in general we get love letters from people after they've been on our wheels for a while. We got three yesterday, so I know that what we use and how we put it together are great. Right now you're a 5, and in stark terms, fancy wheels don't mean s**t in 5s. That kid YYYY (ed - local phenom du jour whose worst race of the 5 or 6 he's done is a 2nd) could ride flat tires and still whip ass, and the guys who don't train get killed. There's too big a disparity in ability for wheels to mean that much. But there's a good timing opportunity to get really nice wheels at a great price, and when you become a 4 and then a 3 and beyond, they can make more of an impact. They aren't SO expensive that you'll be hesitant to use them. I wouldn't necessarily recommend them for the crazy "pretend Roubaix" type races, but I got 5th in Cat 3 at our local "pretend Roubaix" race on 38s last year, they can deal with that kind of crap unless you hit THAT rut that's going to break your wheel no matter what wheel you're on.
That's pretty much it.
In the words of the immortal (and imaginary) Forrest Gump, that's what I have to say about that.