Ooh, that's tough since WL is my favorite resort! I think $400 is worth staying at WL. You have the boat to MK, Geyser Point which is gorgeous at night (and good during the day) and the view of the fireworks/ELP if you're there at night. Plus Territory Lounge is open in the evenings as a non QS option that you don't need reservations for. And the standard rooms there are absolutely fine, in fact your chance of a good view are better in a standard room than courtyard. But that's not to say picking CSR is the wrong choice!
CSR is really fine and like I said, the only "down side" I felt is that there isn't any other mode of transport other than buses. However it's pretty centrally located so no long bus rides; there's a bus stop in every section so you aren't far from one although I suggest not going to the stop at El Centro as it gets most crowded. Our room was standard; Casitas isn't a far walk at all from El Centro, maybe 5 minutes? Very pretty walk
I like their gift shop also but I like WL's too! We had really good bus service, even when we did catch it from El Centro we didn't have long waits just more crowded buses. One other difference from deluxes is that there are 4 bus stops, so depending where you get on/off you'll be sitting through some other stops. Not the worst thing by far but, different. If you go with CSR I'd request either Casitas or Cabanas to be closer to El Centro, unless you want to be closer to the pool; then request Ranchos or Cabanas. Casitas is farthest from the pool and that's close to a 15 minutes walk.
I probably wasn't much help lol, sorry! I know you'll be happy with WL but I think if you try CSR you will, too.