Pioneer DDJ-400 Restock

Hey all, 

I just wanted to reach out after talking with customer support to ask when there with be a restock on the Pioneer DDJ-400 Controller (Silver)? 

I am looking at the DDJ-400 but know that the DDJ-Rev1 is very similar besides software. Are there any other big differences and how much would it cost if I got the DDJ-Rev1 and eventually wanted to upgrade to Serato DJ pro?

Thanks in advance. Any help is appreciated.