@tikiavenger I still really like the C315. The sailing season was soon over when I wrote my comments last September in this same thread, I still feel the same way. This years launch project is to replace the 7 year old 4d Lead acid batteries with LiFePO4s. Actually I do not think it will be that difficult at all. I am looking forward to more cruising in my C315.
I would recommend sticking with the in-mast furling, since the rig is clearly designed for it and it does work pretty well. Unless you are a dedicated racer, I see no downside to the standard in-mast furler. But, then again, if you were a dedicated racer, you might feel more at home in a J-boat anyway. There is track on the aft part of the mast designed to allow you to hoist a hanked on main if you really wanted to.
The saying : "cocktails for 8, dinner for 4, sleeps 2" fits this boat pretty well. I took her out for a daysail with 8 people when I first purchased her and it felt pretty comfortable. The cockpit is roomy. On a trip to Lake Erie, with two other couples, (on separate boats) we had 6 people over for appetizers and drinks down in the cabin and that worked well too. In fact, it felt roomier than the other, larger boats, with us on this trip, down in the salon.
When we went shopping for a boat in 2019, I saw quite a few used Beneteaus and I felt that the Catalina was a higher quality boat with better components. I will be the first to admit that I was comparing different vintage boats in different conditions. But, when shopping for a boat, that's the reality. I never got a chance to actually see a Defour 310, but this article
Our verdict on the Dufour 310 - Yachting Monthly claims that engine access is poor for the Defour. That is a deal breaker for me. Engine access on the Catalina 315 is good.
I hope this helps.