An ECG is only interesting when something is soo of the charts as with downwinder and even then unless you do an complete exercise stress/test under ECG control just an single ECG says nothing and is imo a waste of money.
With a HR as low as Downwinder a ECG should be on the yearly routine of anybody.
I often train with an Suunto Ambit.
You have them in various options. I got the first one that works still excellent and is 100m waterproof.
On my raceboard I attached 2 loops where I put my watch between so I can see while padling my speed, average speed, and HR (or time).
I owned a Garmin before but prefer the software and ease of use of the Suunto.
If you don,t want a HR band get yourself a Tomtom. Pretty cool stuff and very precise.
By far the biggest nerd on gadgets like this I ever read about is DC rainmaker.
He writes lots of very in depth reviews about triathlon gear including HR watches:
www.dcrainmaker.com/