Are you park commandos that are on the go all of the time? Or do you enjoy your resort time?
Unless you're in the parks all of the time and really wouldn't be around to take advantage of RPC, I'm going to vote RPC. To me, it's worth it for the ambiance of the main building, the vibe, the smell, the larger lounge - even if that means a day shorter stay.
I always read that the food offerings are the same, so I assume they are. The "chef's station" that was out a few times at SL a few weeks ago was "trading off" days between SL and RPC, according to the chef.
Having now stayed both one factor that is top of my mind for me is the difference in rooms/views between the two. I'm not sure if there is really a bad room in RPC. You're up high (except for the 2nd floor TPV rooms), most of the view corridors are very attractive no matter which way you're facing, all of the standard rooms have a full balcony (I think, someone correct me if I'm wrong). SL does have a few 'inferior' rooms that are less than ideal... various balcony types, some very large tree views, etc. Granted I did it to myself, but I was majorly stressed about my SL room and room requests. RPC was a breeze. I put a lot of value on the view/balcony experience, so this is an important factor for me.
Although on the other hand, the SL location is really fantastic being steps from the courtyard pool, the marina, boat dock, Gaspy's, etc. It made for an 'easier' daily flow for us.
I found the SL lounge a bit busy at times. We never didn't have a table, but sometimes it was close. Although that can happen at any CL during peak rush hours to some extent.
All of that being said, I booked SL for this last trip because the price was right. I just couldn't pull myself to pay RPC prices!
Tough decission for sure, several pros/cons. Let us know what you decide!