Yeah they shoot well, I think the .22 are a bit better but I sized those a bit. Unsized I'm able to hit a 1 inch spinner at 50 basically every shot with those .25's, as far as groups probably in the 1-1.25" at 60y which is good for hunting. Won't be as accurate as pellets or swaged slugs IMO but very happy with them.
As far as speed as fast as you can get them, I'm set about 145-150 Bar reg pressure and on max I get 780-820 and they're stable at that speed. They are punishingly heavy at 47.7gr or so and they hit HARD.
I initially thought they cycled well but I did have some misfeeds, I think it's mostly the weight and having to spin all that weight with that spring. If you took it apart and increased the spring tension one rotation that would probably do it. I just single load them.