Timex Ironman Road Trainer HRM

So i bought this HRM model and it comes with the chest strap. The previous one I had the Mio Classic was strapless but it died. I am gathering that in order to use the HRM feature I have to use the chest strap. Correct??? So far I love how simple the watch is and that I can wear it for everyday use..unlike my last one which is bulky like the FT4.

I am wondering was wondering what everyone's opinion is of this model and if I made the right choice. Is it accurate with the calorie burn??

Thanks!