Considering it raises test, what are the downsides for long-term use?
I don't know if there are potentially serious long term sides. With clomiphene you risked vision problems, clomiphene was racemic mix of two different molecules, like a mirror image of the other. They say enclomiphene is the "good" one without negative effects. I don't know if this isomer fixes that.
But the old clomiphene was notorious for very negative mood effects like crying spells. Probably because these are actually estrogens. Estrogenic in some tissues, antiestrogenic in others, or a "weaker estrogen" that inhibits the binding of the more potent estrogen.
Users say it just doesn't make you feel as good as synthetic test, even if test doubles or whatever. Probably because of these brain effects.
Oh and SERMs usually lower IGF-1. Back in the day Chad said Ronnie's gains skyrocketed when he got off tamoxifen.
Proviron supposedly doesn't even lower your own testosterone. Perhaps a stack of Proviron + Enclomiphene would be interesting, for a "natural" lol, or for someone who wouldn't want to take his balls offline.
Or just pin test and be done with it.