go yourself because even if you involve an agent you will eventually have to go to embassy yourself, it was straight forward i think i gave the invitation letter (i went there for training), my company letter, visiting card, bank statement, bookings etc ... it was a totally fresh passport i.e. never traveled before and i got it in 10-15 days, this is back in 2012 i think, I went to Munich and i would recommend you to take a look at Econtel Amber Hotels they are great had a good experience with them for a week