Edited to Add:
Have just went throgh the same shopping process as yourself and ended up with a BAC TA31 (donut), which I like very well (after asking my 10,000 quesions of the regulars here ... all of which have been very helpful).
Day after I got the TA31 ran across a TA31f (chevron), which if one was shooting smaller targets (such as tin cans at a 100 yards) would be a nice option. Thus with in 24 hours of paying for the first BAC ACOG started shopping for the second one ....
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Well if you will not be shooting fast at a closer ranges (say under 25 yards) and do not mind a little bit worst image at X4 (darn the ACOG has a nice image), then a nice 3.5 to 10 mil dot Leupold would works well, but is larger.
On X10 from a rest the 3.5 to 10 Leupold will actually probably work better on paper than similar TA01 NSN ACOG due to the increase maginificaiton.
Were the BAC ACOGs work nicely is from close to medium far distances and if you need to shoot quickly (the little glowing donut or chevron is faster to pick up IMO).
Regards
John