well, I'm a little late to the party since you've already ordered. BUT, I have a Nike HR monitor that is a watch/interval timer/stop watch/alarm as well. When you record your workout, at the end it shows you total cals and avg HR. I wish it showed a min/max HR too, but it doesn't. The strap is fine, although it's probably time that I get a new battery too, as the reception seems a bit intermittent these days.
the funny thing I noticed was that if I'm on the exercise bike with the sensor grips for HR, if I'm wearing the monitor, it displays the info on the bike. At first I thought it was magic that the bike was displaying the same HR as my watch w/o holding the sensors
it cost about $100 US
your combo probably gives you more flexibility, however. I'd like a wee bit more functionality on both the HR monitor and the interval timer, you probably get the best of both worlds with your choice.