I'm gonna duck down behind a rock when I say this, but I find Terra Nova tents a bit old - fashioned and expensive. OK the Quasar is good, but it's been overtaken by newer and better designs in my opinion. As far as tunnel tents go, the most tried, tested, and reliable is the TNF Westwind. I've got one and I can't kill the beast. I once went off on a high - level winter trip and cleverly forgot half the tent pegs. Along came a really nasty blizzard. Westwind groaned and flapped but coped easily.
The Westwind has been around for donkeys years because it's so reliable.
The Eclipse is @£360 and the Westwind is £267 at www.cheaptents.co.uk. So it's a hundred quid more for a tent with a lot less of a track record.
I've never used the Eclipse, but I've had a good look at one, and it looks pretty basic, to me...
I've got a Macpac Minaret - also a stomping good tent.
It's all about what takes your fancy though...