I'm a bit of a loss to know how to answer that in honesty since I don't know what makes a heart rate monitor "good". Cateye stuff has, generally speaking, a good reputation so I'd guess their heart rate monitor will do the job. Polar are, if you like, the leading name in HRMs so how does the Cateye compare in terms of price and functions with a similar spec Polar?
A lot depends on what features you want with your HRM (zones, alarms, etc) and how much you want to spend. Lidl & Aldi both have cheap HRMs that either work or pack up, but at their prices it might be a gamble you want to take... if you can get hold of one!
If the Cateye suits your needs and is at a price you can afford then go for it.