Any specific advice on what HR monitors are good/not such a bargain/not worth the money?
1. Do the strapless ones do a decent enough job?
2. What brands/models will do the job and not break the bank?
3. Best merchant partner for getting a good deal?
Such a gray area. There's a few mfg's out there, like Timex, Suunto, Garmin, Polar, etc. No specific order, and not an exhaustive list (but the first that came to my mind). I've not seen good reviews on strapless ones, so you're probably best to stay away from those -- if someone else has better data, then please correct me.
Functions within each mfgr range from just HR data (basic) through full GPS-programmable with HR zones and data logging that you can xfer to your computer. Prices range from $50 for the basics to like $350+ for the GPS enabled models. I think they're all pretty good, and most folks are happy spending the extra $ on a nicer model.
Merchant partners typically give a 10-15% discount to DC tri, so all are pretty competitive deals. Do a little research, give several a call to find out what's in their inventory, and go in a play with them to find one you like. And if you're NTP, I think they'll have a HR training session (and you could wait until then).
There is, IMHO, no wrong answer here. My going in advice for NTPers is don't over invest. You can easily buy EVERYTHING there is to buy and to go top of the line - bike, wetsuit, HRM, etc. If you have unlimited resources, then knock yourselves out, but if not then think carefully about each purchase and consider what will help keep you motivated. In the end, the bets bike in the world will not win you the race - but if you know that buying a great bike will keep you committed to training, then there is no harm in it. For me, I know that the bio-feedback from a good, detailed HRM would help me and so i invested in the Garmin 305. But for many people, a basic sub-$100 is more than enough.
Another thing to consider is what other gear are your going to get? a bike computer? HRM? GPS? if so, it might pay to get all in one. if you are not an electronics/gadget person, then buy a second hand HRM with a basic strap and you'll be fine.
Despite what people (like me) will tell you, it is not about the gear - it is about you. But if you are all about the gear, then . . . . . .