Welcome to the Hide Noles. While there is some validity to the "buy once cry once" idea in theory, I think it doesn't hold true in reality at least for this market. Yes, there are a few out there who bought Scope X years ago and still shoot with it today, but the advancements within the electro-optics industry over the past 5 years have been pretty incredible.
The reason you don't find many reviews is because the TARS never really caught on, not that it is a bad scope but for the price, but I believe there are other scopes that are probably as good or better. From memory the TARS sources Schott glass and is an impressive performer optically, but it's heavy weight and lack of "good" reticle options have kept it on the outside of the industry. I know you're a Trijicon junky, but try not to be a brand loyalist simply because there are so many great options from other manufacturers. If you want top tier quality for about the same price look at the Tangent Theta TT315M, an extreme scope in every way, another option would be the Minox ZP5 3-15. I consider the 3-15 to be the bare minimum for long range shooting, but that is my preference, there are plenty of shooters who've been successful with 10x at 800+ yards, but my personal preference is having 18x or above at the high end. Is there a particular reason you're looking at 3-15's or is it just because that's what Trijicon makes? If you tell us what kind of shooting you intend to do, what ranges and what rig you plan to put the scope on you'll get better response from the community.
One last thing to think about, if there is any doubt in your mind that you might not be happy with the TARS for any reason, the resale on it probably won't be that great because of the fact that the TARS is not a popular model within the shooting community, and if you decide to sell it your return on investment will not be that great. So "buy once cry once" yes, but if you do happen to sell it, you'll cry even more
