Got to agree somewhat with the Cap'n about metronomes.
We have a Morris dance group, when we get a musician with an Irish session background, they always play too fast. In general it comes from the diddelys or triplets, they play them with total disregard to the length of time of the piece (ie. as fast as humanly possible). Then after a couple of triplets they keep up the new tempo, or end up out of synch with the dancers. A metronme would definitely help there.
Unless it was like the one I bought for $5 in a garage sale, it went
T I C K - toc, it took quite a while to get the arm recentred on the shaft.
On the subject of the music/musicallity though, just remember the Police Force advertising mantra "SPEED KILLS"
JohnB.