The Enve's are reported to come in at 1,434 grams, but I haven't weighed the H+ Sons wheels - they have got rotors attached, so these would need removing and I really couldn't be bothered / wasn't that interested as there was nothing I could do about it. Having had a quick add up of the component weight, I think they'd come in at around 1,700 grams.
For a while I only had two road bikes (I know, how on earth did I cope), so used my Kinesis (which these wheels are on) as my full time winter bike. As the weather improved I managed to average 20.6mph on that bike before moving across to the summer / plastic bike. So I would say that they are more than capable of doing quick rides, as long as you are prepared to push hard enough :-)
I have used them for many commutes to work, a hilly hundred and the Dunwich dynamo and they are still round and true. The rims aren't particularly heavy (470 grams / rim I believe) so it would be very possible to build them up with lighter hubs and fewer spokes and probably get the wheel weight down a bit if you wanted. I opted for 28 spokes / wheel so that they would be a little more robust.
I think that were around £400, but they were part of a custom bike build so were bought and paid for at the same time, so I never really worried too much about their exact cost - they gave me a rough idea of budget for wheels as part of the build and that was good enough for me.