I first saw the TNT 80 at a B&M too, was actually looking at it for a friend who has 26650 batteries and glad I did. It really impressed me but they wanted $80 + another $14 for a single battery, with tax it was going to be over $100 so I passed. My friend actually found that sale price and as soon as he emailed it to me I ordered it right away. Having the extra battery really helps too, 26650's take awhile to charge so having a charged battery ready to go keeps you running all the time. I haven't used the pass through for charging but my friend uses it for his 4 hour round trip commute to work sometimes and he says it works great.
I use my TNT more than my Sig 150TC now because it is always on the road with me, it has been flawless and a insane deal for the price. I did order a Wismec Reuleaux DNA 200 but I am thinking that will replace my Sig 150TC and the TNT will still be my road dog. The price is cheap by comparison so if I drop the TNT it won't be a OMG moment compared to the $150 Wismec.
I don't know if anyone that has bought the TNT hate's it, it is usually quite the opposite. Just buy it, you will love it!