Not even close... UBR is a little heavier, but way more solid. For me, it helps balance the nose heaviness of the swat version. Well worth the $.
Only issue is if you plan to put a cheek riser on it, you will have to find the older version or someone who has the narrow top plate to make it work. They only come now with the wide plate, the older version use to come with both. May have to call Magpul and get one, that is what I did on my last one.
I've got a UBR on my 556 and a CTR on my Bushmaster 450. Though the UBR is a bit heavier and solid as a rock, the CTR has stood the 450 Bush recoil just as capably and locks up very solid with its mechanism. I don't believe you'll find either one less than outstanding. Certainly the CTR costs less.