I'm now back into cycling after a long time off the saddle. 15 years ago, I used a Vetta cyclecomputer with HRM and it worked great. It displayed my current HR and I could set lower and upper limits and the screen would flash if I was out of my specified training range. At the end of my ride, I could view how much time I spent above, below, and within my training range.

Back then all the HRM related training advice I heard was to determine your max HR (through either a stress test or 220 - age) and to ride between 65-80% of your max HR for aerobic exercise, and > 85% of your max HR for anaerobic interval training.

I recently picked up a copy of Base Building for Cyclists and see advice for determining five zones which are primarily based on power output and secondarily on HR. Training rides consist of spending certain percentages of your riding time in some of these zones.

I have no interest in shelling out for a power meter - it's totally overkill for me anyway. I'm not racing but want to track my fitness level and set and achieve goals.

So, being in the market for an HRM again, I'm wondering if I should just pick up something simple (the cheapest Polar wristwatch HRMs have the features I used to have) or find something that could let me set up 5 zones so I can follow some of the newer training advice I'm reading about.

Any suggestions, especially for particular models? Is there anything else I should know about HRMs while doing my research?