I curently own a TNX 5.2 and I think its a great truck. Its crazy fast and jumps great. The only problem I have is that if you need parts you will no doubt have to order them. Hobby shops just dont carry Tamiya parts. I dont know anything about the Hellfire but HPI stuff is generally top quality. I think you would be very happy with either one. Here is a pic of my TNX that I just put new wheels and tires on. Proline 40 series Mulchers and Axial black chrome beadlocks. I put the old style TNX body on because I just dont like the 5.2 body.
My "LHS" Carries Tamiya Tnx, and Tamiya Nitrage, and if i enjoy my new hobby of rc (yet to get the first one) but if it does take off, i may consider getting one or the other, any opinions?
I like the TNX as I stated above.....I have never seen a nitrage run. The guys over at Tamiyatrucks.com would have all the info you need about both trucks.