I had a rifle, until I traded it recently, that had a UTG 4 rail fore-end. It worked fine, I didn't have any issues with it. It was NOT as rigid as any of my others. Did it do the job? Sure, what I used it for. I would not have used it for anything more demanding than I was. Would I expect to see UTG on a rifle costing, say, $1400+? No. And I wouldn't pay that for one. I could see using UTG for prototyping, or low stress purposes such as I was.

If someone wants a specific manufacturer, that's up to them. Don't flame 'em because they like something specific. Doesn't make them wrong. Doesn't make you right. Whether it's upper end or lower end. If you just enjoy arguing, that's another story!