Very Very useful and good value at around the £20 mark (Feb 2010).
As my first Tuner, it does the job for my classical, accoustic and electric bass guitars. Its accurate too - so far I seem to be perfectly in tune with CDs etc I play along to or friends with other instruments.
I do find it a little slow to settle down and confirm the note being tuned when using either the internal mic or the input but have nothing to compare it to, this could just be me being impatient.
The metronome, has loads of signature settings which I am slowly getting to grips with. My only gripe is that it has a fixed volume and a little quite for my liking.