If you want the P6T deluxe because of it's features, then as the prvious poster said, £20 is nothing to stretch, even £50 is nothing. It's all relative. Personally I would stretch that £20 and not buy myself a pint this weekend.
The DFi seems to be a good board, but you have to read the reviews on each one, and decide for yourself. When I was choosing mobo's I asked a similar question on another forum. One guy said "If you want great overclocker, get the Striker II Extreme". I read the reviews, and thought "WOW" this is for me. That cost, and still does around the £300 mark. What I didn't realise however, that you need a watercooling system to run it at the speeds those people talked about. End result for me: going to have to spend £300 again on watercooling this summer so I can achieve a decent OC on this board.
What I'm saying is that these forums are grea, but don't listen to one person's viewpoint over another. Just because someone likes the "look" of a certain product over another, doesn't mean it's a better product.
At the end of the day, it all comes down to:
A: What you can afford
B: What you need out of it
C: The most popular.
The P6T deluxe is a popular board because it is a very good one. You still haven't said what you need your board for? Are there any features in particular that you're looking for? Like number of PCIE slots etc? Or just a good clocker?