I was there this weekend and rode the bike park. I had a good time, there's a lot there. But both times I went there (it's quite big) I was the ONLY bike there. There were weeds growing in some of the lines, and a couple of the expert jumps/drops were not rideable due to eroded take offs and landings.
It's definitely worth going, but it not running at 100%.
The town is only like 12k people, and there just isn't the population to support a park that good. If that park were in SLC there'd be 50 kids in there every night, easy.
FWIW, the trail Valle Del Lobo was a lot of fun, it's new as of late last year.
I do agree that the vertical is just not there for big Enduro type riding, but it's certainly worth a visit. I ride a lot of great areas (living in SLC, UT), and Green River is worth a once a year trip for sure.