Cardiosport HRMs?

I'm looking for a new HRM - had a Polar M21, but never been very happy with it - dodgy buttons and is now not working after I dropped it (only 1 metre!).

I've heard Cardiosport ones are reliable - I want one for under £100, and I like the Autozone one, but is the way it calculates the 5 Target heart rate zones accurate (via maximum heart rate or age)? I currently use the WHR method, which takes into account resting HR. I liked the "blobs" that came up on my Polar M21 when I had burned 100 kcals. I would like one with interval timers, but think that only the top-range Cardiosport monitors have that.

Also - the size of the watch - I have read that some of the Cardiosport ones are bulky - GraphX, Xtreme & Heartsafe - if you have "skinny wrists" (see http://www.heartratemonitor.co.uk/cardiosport.html ). Are they too big for the average female wrist?!

Does anyone use Cardiosport & can give me some advice? Thanks!

Just ordered a cardiosport Xtreme, for just under £100 (just!) - so I probably help (at least with the size question in a couple of days...
How big is your wrist?

15cm diameter & about 5cm across! Thanks...

Got it, and it is quite large... The base of the watch is about 55mm long. Tried it on the nearest female wrist I could find (not an average one!), and although the strap did up, it wasn't ideal. Sounds like your wrist might be a bit bigger though so if you don't mind a watch that's a bit bulky it might do.

in terms of heart rates, I think it does the following:

Max is set either from age, or manually. This is used to display current as a percentage of max.
Two zones are programmable with a range of 5bpm - one is selected at any one time, with independant high/low alarms.
So if you use whr, the percentage displayed won't be right, but everything else is done in BPM, which is independant of any other variables. There isn't anything related to no. of cal burnt (but that's got to be a wild guess anyway?), and it does intervals based on time or heart rate recovery.

Shame the instructions are rather brief - just 20 very small pages.

Hmm it does sound a bit big - my current polar watch is only about 45mm. I was thinking of getting the Autozone monitor (with 5 zones I think) but I like the fact that the Xtreme has an intervals function. It's annoying that you can't program them to use WHR formula instead of direct % of MHR - the 60% values are ridiculously low (all I need to do is get out of bed to reach that!). Thanks for getting back to me!

The calories burnt function is more of a gimmick really, but can be useful as a rough estimate / motivator, if one of the reasons you're running is to lose weight.