I have a couple of opinions.
The first dedicated carry belt I bought (after years of wearing out cheaper belts) was a 1.75" leather belt from 5.11 Tactical. The belt has a plastic stiffener laminated between two layers of leather, which is really good for preventing sagging etc.
My only complaint was the sizing. When I tried their medium, I was at the very last hole on the belt. When I tried their large, I was at the second-from-first hole. Even though that was a lot of "leftover" belt up front I bought it anyway. But now that I've lost some weight...it doesn't fit. (I'm 5'9 and just over 200 lbs.) I might wear it again someday, but I'll have to take it to a leather shop and have them cut it to fit me. Interestingly, I notice that 5.11 has discontinued this line.
So after relegating the 5.11 belt to the "old holster drawer," I bought a 1.75" Rigger's Belt from Elite Survival Systems. Belt and buckle are rated for 7,000 lbs and emergency rappelling (you know, just in case - haha) BUT the good part is that the nylon doesn't stretch at all. So once you cinch it down in the morning, that's thwere it stays. It does a great job of holding up my pants, even when weighed down with a fully loaded M&P 45 and 2 spare magazines, and sometimes my cell phone too.
My only complaint is that the Riggers Belt looks WAY too tactical with the odd buckle, and those who are familiar with it may mark you as carrying, even though your firearm is completely concealed.