Of the formations which play with three up top, I personally prefer to standard variant, which has
three central midfielders, over any others. This is due to the fact I like to have my players as centrally as possible, and then affect their position with instructions, rather than force them into a role using positions such as CDM and CAM. This formations utilises two wingers, rather than LM and RM, which can cause opponents a lot of trouble. The most common usage of the solo striker is a target man, but Barcelona have seen success with Suarez in the centre, so a ball playing striker is also a possibility. This, by the nature of having three players pushed very high up, is an attacking formation, but can be altered to be a brutal counter attacker too.
Advantages – With the wingers pushed so far up, they contest the LB and RB, and if these players regularly get forward, the LW and RW will expose the gaps left. They also create trouble for the standard two CB’s, as they will make runs behind them, either getting the ball themselves, or opening up space for the solo Striker to receive the ball. It forces the opponents LM and RM to want to deal with the wingers, and the three in midfield contest any two midfield formations heavily. With the right personnel, the three central midfielders can become either playmakers, defensive guardians or box to box midfielders, which is such a useful decision to make.
Effective vs – I believe 4-3-3 shines vs teams which attempt to utilise attacking LB’s and RB’s (not a formation, just a playstyle) and also teams with only two central midfielders. This is due to the fact the three in midfield outnumber the central midfielders, and will generally not be closely marked by holding midfielders. Furthermore, this allows the LW and RW to be unchecked if
they do mark your three midfielders, creating space and allowing you to exploit gaps. The 4-3-3 is usually composed of very fast players , to absolutely expose the lapses of defense which will occur during a game.