The HTC Radar ships with a respectable 1520mAh battery. Remember this isn't a dual core smartphone, so for a 1GHz processor and average-sized screen, this should see you through a day of use comfortably.
HTC claims you'll get 485 minutes of talktime on WCDMA 3G or 600 minutes on GSM, and 535 hours of standby time on WCDMA or 480 hours on GSM, but this is always dependent on so many factors including where you are, signal strength and so on.
We took the HTC Radar off a charge at 7am and spent about 20 minutes fiddling with various settings and catching up on Twitter. Over the course of the next few hours, we sent more than 30 emails, a couple of texts and made a 21 minute phone call. Mid afternoon, we went running for 90 minutes with the RunKeeper app going, and listened to the FM radio for about half an hour in the early evening.
The HTC Radar kept going, and even by 10pm it still had about a third of its battery left. We didn't use it much the following day and it managed to last until lunchtime before conking out.
Our impression from this is that if you're a power user, you'll probably just make it through the day. But if you're a light user, you'll get so much longer out of it. However, remember that the battery isn't removable, so if you do get caught short, you could be in trouble.
All of the usual suspects are on board connectivity wise: Wi-Fi, Bluetooth (which we seemed to be unable to use to send or receive files, bizarrely) and GPS. DLNA is catered for, as it is on most handsets these days, but there's no NFC chip. We won't rue that too much, since it's not really caught on yet. Only BlackBerry seems to be religiously pushing this at the moment.
3G works well, and internet pages loaded quickly with no fuss. Wi-Fi boosted those speeds even more. You can also use it to tether to your computer if you wish, but remember that your service provider may see dollar signs in its eyes if you do. GPS was fine, and got a lock reasonably quickly. It wasn't so quick that we were bowled over, nor was it so slow that we noticed.