Personally, here is what I think, purely based on speculations and what I have seen from the artists so far:
Surprise
1.
Israel 
: Eden is of course going to give her all and perform the heck out of the song. She has shown how much of a stage presence she can give. I am sure despite having a not so well-received song, she should be able to elevate the song even further with her charms and charisma. Israel usually doesn't do that badly with staging, so I am pretty confident they will get the staging right to complement the song and Eden.
2.
United Kingdom : I just have this gut feeling that James is able to pull off the song. I understand there are comments that he looks awkward with his moves in the music video. But I am sure he will be able to get more comfortable with more practices. Staging wise, based on the leaked plan for his last year's song, I am certain they will be able to come out with a good staging.
3.
Germany : Although I really dislike the song, but I can see Jendrik putting his charms to work and elevate the song further. I can definitely see him snatching televotes from the other quirky acts like The Roop and Dadi.
4.
Czech Republic : There is something about Benny that makes me think that he is able to bring the fun energy on stage with the song. If the staging is does right, I can see it doing really well. Who knows he maybe able to do a Lake Malawi.
Letdown
1.
Cyprus : I just feel that Elena is going to be a major flop on stage and struggle vocally even though I don't really know how she sounds like 'live'. I can see her doing more of a Tamta rather than Eleni.
2.
Switzerland : While I know Gjon's Tears has an amazing voice, but he needs to work on his facial expressions especially when he is trying to hit the high notes. Plus, with SJB behind his staging, I am just afraid that he may not be able to have the right staging to complement his song.
3.
Moldova : While she has the "dream" team behind her, so staging wise she would be alright. But I feel she is going to sound like a trainwreck 'live especially if she has to keep up with a routine.
4.
Finland : While they can pull off a high energy performance, but vocally the lead singers are really shaky and inconsistent. I won't be surprised if they may sound way off because they are so into sustaining the high energy throughout the performance.
