The stillen setup offers a z-tube with the intake. The stillen also uses an oiled filter which is not the best for filtering and a slim chance of maf issues.
The r2c offers there own tube design if purchasing the MaxxFlow Intake. The filter is designed to flow well and filter better than the competitors, which is very important.
http://r2cperformance.com/technical-advantages2.html
Read up on the r2c filter and make your own conclusion.
I have used the JWT setup, which is similar to stillen. I now have the R2C setup and it is by far superior.