Yes it's worth it. Freeview has improved a lot the last few years with channels like e4, more 4, film4, Five US, Five Life and UKTV History. There are a couple of 24 hr news channels (probably not for much longer), couple of music channels, shedloads of radio stations.
However freeview is under a lot of change at the moment. Virgin have just launched Virgin 1 channel on it. UKTVG2 is about to go on freeview badged as "Dave".
There's also a lot of other goings on. There's currently a public consultation on DTT on whether Sky should be able to bugger off and use it's space for pay tv called "Picnic". As well as that the BBC and Ofcom are pondering whether to launch High Definition on freeview pretty much straight away or to wait for switchoff with various options.
If you want to be pretty much guaranteed a perfect signal then get FreeSat next year.
The best freeview checker is
http://www.wolfbane.com/cgi-bin/tvd.exe?
You may not be able to get all muxes.
This is a list of freeview channels by multiplex
http://www.digitalspy.co.uk/terrestrial/mux/
You're pretty much guaranteed 1. C and D tend to be dodgy in quite a lot of areas.