Yes, I have a 5000 that I've used since they first came out and am still very happy with it. Caught plenty of tuna and dorado on it and even use it fairly often for jigging bottom fish or chucking swimbaits into coho schools in the ocean. It's definitely a legit big game saltwater spinning reel that, in my experience, is pretty much on par with the Stella but comes at a much more reasonable price. It's total overkill for salmon and steelhead or any kind of fresh water fishing in my opinion but makes for a great saltwater reel.
As for Vanford, my understanding is it's basically the new version of the stradic ci4. I got a 3000 earlier this year and used it a little towards the end of winter steelhead season and have been happy with it so far, but with only limited use to date. I really wasn't able to notice a difference between it and the ci4's so I assume it's going to be a perfectly suitable replacement for that product line which used to be my go-to salmon and steelhead spinning reels.