I believe this is an investment play. I look at 2 things before making an investment play: 1.) does the team have the talent to win, 2.) does the team have the motivation to win.
Regarding talent, certainly Croatia has the talent by virtue of beating England last year. Austria is a host country so they get a place automatically, not because they have the skill to be here.
Regarding motivation, Croatia will want to pull out a win here to get a leg up on the competition and to put the pressure on the Germans who have not played well in the friendlies..
Croatia's first win against England was largely a fluke. That England team went down 1-0, then Robinson COMPLETELY missed a pass from one of his defenders, slipped and the ball went in. If this hadn't happened, I bet England would have come out with atleast a draw, but that slip up really hurt the team motivation. For the most part, I view Croatia as an average squad who will really battle out Poland for 2nd in that group. Croatia got a bit lucky with England being so poor in qualifiers and having a below average group.
Spain is definitely my pick to win it all. They are simply the most talented team. Their young stars are now much more seasoned than they were in the WC. Torres and Villa on the attack is SCARY, to go along with Fabregas in the middle. If Spain matched up with Italy in the quarters, I think Spain's youth and speed would crush an aging defense. Plus, Spain's group draw is favorable, with an easy win against an outmatched Russia, and a win from either Sweden or Greece, would be a nice warmup for that squad.
I disagree about Portugal. I think Nani will perform well, and obviously having Ronaldo up front will take the pressure off. Plus this team still has Carvalho and Deco. Theres enough talent to top their group.
I disagree with Switzerland. They may be the most boring team in the world to watch. They have good ball control, but almost never have a good enough attack. I see no chance of them beating Portugal or Czech Republic. If they get to the quarterfinals, its only because of home advantage. The fact that they didnt have to qualify for the Euros will only be a disadvantage for them.