I listen too, just not as impressed with non-Ra performances. My premise is really quite simple: Gilmore plays so much better with Sun Ra than he does elsewhere, it just leads one to wonder why. Was it something with Sun Ra, or something innate to Gilmore. Probably both: Ra's overarching structure, and Gilmore's need to play with people he was friendly with. I don't really know, but find it a curious case.
That Dizzy Reece LP he's on is stunning. Leeway, I suggest giving it a listen. I don't have a ton of Ra (just never got the bug), so my listening to Gilmore - with La Roca (as badly recorded as that record is), Bley (ditto), Hill, et al. - has been mostly these non-Ra sideman dates, and he's never failed to deliver heavy goods.
I just replayed the CD of that album ("From In to Out"), and while Gilmore does get off one or two good volleys, he's probably the 3rd or 4th most effective person on the album. Not knocking his performance, just saying it doesn't set any new bars for me. But I'll reconsider if I'm being too hard on Gilmore, and give me something to think about when I listen to Sun Ra.