I have never shot with one. I have seen and played with a few that were mounted on some AR replicas. I would like to have gotten one for a new rifle I am building, but I dont have that much right now. The TA55 has the BAC feature which is a great advantage over the non BAC TAO1nsn. I think you will appreciate the advantages of a BAC model ACOG over one that does not have that feature. In which case I think you might like the TA31f just as well. It has a similar reticle to the TA55, it has the BAC like the TA55, it has 4x like the TAO1 series, which is only 1.5x less than the TA55, it is 1/3 the size of the TA55 and probably half the weight. Basically, unless you feel like you really need that extra 1.5x, I think the TA31 series will do you just fine. And you should be able to find them here for less than $900.