I have a Burris MTAC that I picked up for $343 shipped from
The Sample List. It was in new condition. Get the correct reticle for the bullet weight you typically use. Keep in mind you can check the calibration for different weights and the dot will line up with a different distance.
1-4x for sure, but do take a look at 1.5-6x from Leupold. I had great results from 50+ yards. 6x (actual is 5.5x) made 100 yard shooting easy. However, for 25-50 yards you're going to want at most 1.1x on the low end. 1.5x slowed me down at 5-25 too much; it was decent from 25-50.
Are you going only take shots within 100 yards? What ammunition do you use? What bullet weight? Take a look at ballistic charts and figure out your average distance and which zero has the least delta over +- 50 yds.