I'm also a big fan of Cafe Nero. However if I am somewhere, want a coffee and have a choice of the big chains, then I'll pick Starbucks if there is no Cafe Nero.

The reason is consistency. Starbucks clearly train their staff better than the other big chains. If I get a coffee in a Starbucks then I can be reasonably sure it has been vaguely competently made. In the other big chains half the time you end up with a cup full of milk with a distinct lack of any coffee taste.

So Starbucks might not have the best taste, but at least I know what I am going to get and that it is likely to be drinkable.

Edit: I have an exception to this rule, if I was in Seattle then I'd choose Seattle's Best Coffee instead, unless I was at Pike Place in which case I'd be at _the_ Starbucks, just because you can...

(actually in reality if I was in Seattle I'd probably be drinking a Tully's Espresso Shake in preference to a coffee)