Santos isn't THAT bad he just looks fat and lazy, hopefully he'll get into shape. He wins quite a lot of tackles and is absolutely great going forwards, easily 50 times better than Clichy. I'm pretty sure he's matched Clichy's entire goal tally from about 6 years in about 6 games.
Santos is catagorically not better than Clichy going forwards. Other than Clichy being fairly desperate for a goal so trying some daft shots in the past year he's very good going forwards and has been so for City. The problem was at Arsenal, his crossing was wasted because of who we have upfront/the way we play, and we haven't had a left side partnership since Pires left. Clichy's interplay with frankly whoever plays left wing at City is quality, good passing, running the overlap, getting in behind and putting a cross/pass into a dangerous area. Again none of this really happened at Arsenal as we haven't had an established left winger, nor did the team play in a way to take advantage of it.
Santos is just a bit rubbish, yeah, he got a goal, Ramires disappeared, Bosingwa just randomly from having the area completely covered runs infield about 15 yards to stand right on top of Ivanovic leaving a huge gap. Clichy would have scored that goal, his defending was abysmal in the first half and the only real difference in the second half, was Chelsea got even worse.
Guys I did specifically state Brazillian defender, which rules out Baptista and Denilson, if you merge your criteria with mine that would mean a Brazillian defender at Arsenal, realistically that means Sylvinho, who was better than Andre Santos
I loved Sylvinho, I'm still not sure if its rumours or not that we got rid of him quickly due to a sticky passport situation. Cole was awesome at the time but its a shame we lost him anyway.

United's full backs have probably scored less than 5 goals between them in the last 5 years and we seem to have done all right. In fact, I can't think of any goal scoring full backs apart from Dani Alves.
There is a few, more than a few, though most who score, Alves included, tend to take a lot of freekicks and some penalties, like Baines for instance. It is quite funny that there aren't any high scoring (from open play) fullbacks at the moment seeing as there are frankly so many ultra attacking fullbacks who, to be honest, aren't very good at defending.
But there is the problem, a HUGE number of fullbacks at the moment aren't awesome awesome left backs, who could be awesome left wingers, and are great at shooting. Most of these awesome attacking fullbacks are failed wingers, who aren't really quite good enough to play on the wing, so get pushed back. You end up with a winger who isn't good enough to be on the wing, pushed back, and isn't very good defensively.
I think its party too few kids wanting to play as fullbacks so try and make it as wingers. Where as older fullbacks maybe focused on defending and we had the odd one who was awesome going forwards and would get goals aswell.