I have had the Babyjogger Performance for over 3 years now and still going strong (2 children later). As far as I am aware, due to some European Heath/safety guidelines that won't cover anything above walking speed, they are no longer being imported to the UK but you should still get one on eBay as they come up frequently. Friends have had the Nipper which is heavier but quite sturdy and pretty useful as a day to day buggy too.
More expensive but great also as a bike trailer and for hiking is the Chariot Cougar - we have the double version which I used for a year when my second was born (and still occasionally though they getting too heavy for anything but the flat and a slow plod!). Again if you can pick it up second hand they are good value and have little wheels to convert to a regular buggy too.
Still, the Babyjogger Performance gets my vote (though I should say not suitable for running with baby until officially 6 months or when they get head control - 5 months for my first and 4.5 for second).
I'm most definitely interested. Only just started running again and will be fitnenough soon to take both out when baby big enough. Tried to pm you but not working for some reason. Where do you live? Pm me if you can and I'll send you my mobile number.