Heart rate monitors?

Has any one got any experience of using heart rate monitors and if so what did you think? I'm thinking of getting one but was wondering if other people rate them at all or if they are just a gimmick.



There are lots of articles online and a few studies and things relating to them but I'd appreciate some qualifications data here, some opinions and such :)



Also if any one has any ideas as to what models are good/rubbish that would be awesome :)