Trending @Wipro; Should I switch to my previous company?

Hi.. in current company, My project last date is June 30.. I believe there are many projects available for C#.net and now my previous company manager reached me to join back with promotion but for sure there the project will be very hectic.. also, I am not sure how about the hike percentage they will offer.. that I need to check with HR after interview process.. so which is better? Stay in current company with same designation and look for other project or go to previous company with promotion ? Pls suggest