Great TR! We went to Wintertraum on opening weekend, which was extremely crowded. It still was a fantastic experience, as always. And for anyone still going, make sure to be at Kaiserplatz around nightfall when they switch on the lights. Grateful to have such an amazing park nearby!
Wintertraum is amazing! It's not that much different at daytime, but once it gets dark...oh boy! I would still avoid the weekends though, to be perfectly honest. Way too crowded on my last few visits. I posted a short TR of the 2015 Wintertraum, if you want to have a quick look: http://www.themeparkreview.com/forum/viewtopic.php?f=2&t=71299
Matamba should be slightly cheaper (10-20€ if I remember correctly). No matter where you stay though, be sure to check out Dragon Bar at the Ling Bao. One of the best theme park bars I've been to.