From what I have read many disagree you don't need one but I think it's a handy device to waste my money on anyway.
I am looking at a couple. I have a voltmeter but this combo looked interesting to throw into my box.
http://www.horizonhobby.com/Products...?ProdID=HAN111
And this one is justa straight tach~
http://www.horizonhobby.com/Products...?ProdID=HAN156
Any comments one way or the other? Both by Hangar I see.