I like my polar RS800SD for the PolarProTrainer 5 Software it comes with. It allows very deep analysis if what is going on with your training including planning exercises. I'd definitely figure out what the best Polar is that has the features you need at the right price.

If you're a cyclist/runner I'd seriously consider getting one of the polar's with a footpod for running for sure, and possibly a power meter. Those really let you scientifically manage your training

Here's both a favorable and an unfavorable review from Amazon.com on the F7:

The favorable:
This heart rate monitor works great. I have no problems getting a reading from the watch or from the gym equipment that support Polar "broadcasts". Having said that, the rest of the review will be about "Buyer Beware" points. Buyer Beware Point 1.) From what I can tell, the F7 offers the same features as the F6. In fact the F7 came with the F6 owners manual. I say this because at the time of this review, you can purchase the F6 on amazon for around $96 vs the $119 for the F7. The F7 does though come with a material elastic chest band for the monitor where as the F6 comes with a plastic chest band. The elastic is supposed to be more comfortable and this is why I justified paying the extra $25 for the F7. Buyer Beware Point 2.) You have to wet the connectors of the chest band to get it to read your heart beats. Now many of you may already know this. Being a first time buyer, I didn't. So I can imagine how gunky this thing is going to get over time. They recommend rinsing and wipe it down after every use and after 3 to 5 weeks of use to wash it in the washer machine in a washer bag and limited detergent (NO BLEACH!). The probes on the strap are a material mesh and look like if I were to repeatedly wipe it down as suggested, will fray. Buyer Beware Point 3.) The battery in the watch is stated as lasting approximately a year. It will be shorter if you use that backlight. In order to have the battery replaced, Polar advises that you have to send it to an authorized Polar service center or it will no longer be under warrantee (which I believe is 1 year so if the battery lasts that long, you are in good shape) and it will no longer be water resistant. I live in the NY City area and there are no Polar service centers near me. In fact, the Polar web site only lists 4 of them in the USA. So when the battery dies, I will be left without my heart rate monitor for days if not weeks while it travels to and from the Polar service center. Given, all of this, I still recommend the product as it works great. I just have to adjust my expectations that this may not last for years and years which is what I was hoping for.

Now the unfavorable:
We purchased both the female and male version of this for Christmas and like the Polar Heart rate monitor. The watch is easy to use and the cloth bands make it worth the extra few dollars from the F6. However for the last several weeks we have tried to download our data to the Polar Web link (free tools for tracking workouts) and it has failed. We tried two microphones, multiple settings, two computers and none worked. We emailed Polar for help and no one ever responded (9 days ago). Since that is part of why we bought Polar.... it is very frustrating. I have given up.

I only found one review for the Ironman:
I finally got a heart rate monitor after searching a long time. It seemed every time I would decide on one and then go to buy it a couple days later, it would disappear or cost a lot more. This monitor is nice after you get the hang of it, which took me a little while. It picked up a signal pretty quickly and the chest strap stayed on nicely. The calories burned seemed way to high, which disappointed me. It said i burned 680 calories during a 50 minute Jillian video. While, I was in zone 3-4 mostly, it still seems like an overstatement. Overall, it does it's core job and the zone feature is really handy.

It sounds like the Timex may be the better monitor.

Hope this helps! Mahalo!

I have a Polar monitor, so I may be biased. However I have played with the Timex range and I found the Polar to have a more rounded feature set. The ability to upload your training program to a website is a great feature. I don't see that feature listed on the Timex site, but it may be worth checking. I found the Polar compatible with the gym equipment at my gym, Also worth checking.

Hope that helps