I've flown with Excel 5 times (Tobago and St Kitts) and can agree with Jo B's fair-minded comments about Excel - the Business Class is a worthwhile upgrade and good value compared to Virgin and BA's premium seats. Most times I've flown economy and would say legroom is now better (only slightly) than Virgin and BA but you don't get seat-back TVs. In relation to punctuality, it sounds like Jo B experienced a bad delay but none of my flights was ever more than 30 minutes late departing. Maybe I'm just lucky.
You'll find personal horror stories about every airline if you look for them but the fact is they all have problems from time to time (don't get me started about my last Virgin flight to Florida.)
But I've noticed before that you can also get a "fixation" with one airline or another e.g. I'm sure David Watkins won't mind me pointing out the number of plugs he gives to Virgin - is it something about men with beards?
Speaking for myself, apart from the colour of the upholstery I can't really tell the difference between any of them - so perhaps the convenience of a particular departure day is important (e.g. if you want to fly on a Saturday, then you can only choose BA or Excel) or maybe price will be the deciding factor for you. Good luck with whatever you decide.