I have a DDM4 with an Aimpoint PRO on it, and I would like to have a 3x magnifier for shooting longer every now and then. I don't know if I would use it enough to justfy well over 500 bucks on a top notch one. then again I could fall in love with it and use it all the time. You guys are usually pretty dialed in on good opinions when it comes to these things IME. How do the 100 dollar 3x function? Is one worth buying?