Although I don't have the Zvezda version to compare for sure, it's apparently a reboxing of the Toko kit (see Massimo's comment at the very end of the following article):
http://mig3.sovietwarplanes.com/il-2/zvezda/zvezda.htmJohn
(Edit) Fool that I am, I'm at work at the moment, but if you want, leave a reply and when I'm at home, I'll dig out my Toko and Dakoplast kits and compare them to Massimo's images on the above article. There are several 1/72 Il-2 articles on the vvs.hobbyvista site, but none of them shows sprue images, and one actually says that the Eastern Express kit (which Massimo references, IIRC) is the Dakoplast kit. Either way, the direct answer to your question is that it's a reboxing, not a new kit, but let me know if you want more information.