I had always heard that the TRF shocks were the best without a doubt. People would often replace other car's shocks with TRF units.
I had them on my TA05, and frankly I wasn't impressed. I built them properly, but I didn't see anything special. And after one outdoor season, I opened them up and found black oil. Hardly what I would call the best hands down.
Other people swear by them, but I just wasn't impressed.
My favorites so far are the Losi JRX-S shocks. They were the only thing about the JRX-S that really impressed me. Everything from putting on the ball cup to installing the pistons to filling them is well thought out and simple. They are super smooth! I'm able to build them consistently every time, and because of that, they are the first shocks where I don't consider it a pain to try different shocks oils between races. And when I open them after a season of racing, the oil is just as clear as when I put it in. And it doesn't hurt that the gun metal grey color and knurled surfaces look great.
Best of all, you can get a complete set of them for really cheap.
I currently use them on my TA05. When I get my Mi3, I'll see if those shocks are all that great. I'll see if AdrianM's comments about them being 'THE best in the industry' are true.
If they don't impress me, then a set of the JRX-S shocks will be going on that car too.