I agree with dell Boy, he's been flattered by having the likes of Fonte, Van Dijk, Bertrand, Wanyama, Romeu, Spiderman sat in front of him.
I'm no expert but I've coached kids goal keeping and have played in goal throughout Tyro League, Schools, College, University and Soton adult leagues, and I've never been a fan of Forster from day one. The first thing that struck me was how slow off his line he is, time and time again. This comes down to speed of thought and reading the game and can only partially be taught. Add to this his poor kicking, slow foot-speed and lack of commanding his box and you get an average keeper. Giver him his due, he is one of the best in a one-on-one situation, mainly down to his stature and isn't a bad shot stopper if the ball isn't hit hard and low.
Going back to before McCarthy got put in the team, you could see the lack of confidence in the defence as they never knew whether Forster would come charging out, or come for a cross and this should be something defenders don't have to worry about. McCarthy has been top drawer since he's come in and is now showing the form that got him linked with England in the past. His display on Saturday was phenomenal and could well give us hope of staying up.
Watching McCarthy closely (as I do as a nerdy ex-keeper), reminds me of watching Schneiderlin in a weird way. My non-Southampton supporting mates used to ask me why Schneiderlin was so highly rated as they don't see him do much, but as we know, it was all the small things that he did effortlessly week in, week out that made us sit up and take notice - not 35 yard barnstormers or dribbling round 4 or 5 players. McCarthy is the same, his footwork, coming for crosses, reading of the game, communicating and kicking (all the bread and butter stuff) are done naturally, but they're not the things you normally get noticed for.
If you haven't guessed, it's McCarthy all the way for me!! Bring on The Swans - COYR!!!