When I bought my PS3, there were no new Slims available, all replaced with the Super Slim. I ended up buying a used Slim anyway for various reasons including the cheaper build quality/build material of the Super Slim and the fact that the Super Slim had no price drop over the regular Slim.
As for noise... I'm sure my PS3 runs quieter than my PS4 lol, though I now have that (not included) piece of plastic called a PS4 cooling stand that they normally ask £20 for (I got my stand for £12). I've not played the PS4 since getting the stand, not enough time to play games :s