We did both for breakfast. The food was no better at one than the other...both were standard breakfast...good, not fantastic (but it's breakfast so I don't expect fantastic). Both character interactions were great!
I will say that eating inside Cinderella Castle was A-MA-ZING!!!! If you haven't been, then you can say that you don't really know what you are missing. You're kids would get an equal level of princess interaction at Akershus (unless they are huge Cinderella fans...which my littlest is). Akershus itself is "quaint"....reminds me a bit of La Madeline's inside. I too will also not have a problem dropping the Akershus ressie once my girls outgrow the princess phase but I will always try to get a CRT ADR. Once you eat at the Castle....how can you not go back?? It is an experience in itself and quite magical. We have ADRs for both again. Is the food worth 2TS credits? No. But I think the experience is. Last time we paid this one OOP so we would have enough credits for every night (did not plan that effectively btw) but this time we have DxDP so I did not hesitate!
I have not eaten lunch or dinner at CRT and as those reviews are spotty, I would not. If I had horrible food somewhere it would probably taint the experience for me too. But we had breakfast and as it is kinda hard to mess up breakfast so this didn't happen for us. If you do decide to do it, my advice is to make a CRT breakfast ADR. It is a wonderful start to a day in the MK!!