Waterproofing a textile Motorcycle Jacket

After four years my motorcycle jacket needed a wash and it will be its first. The wash cycle will remove the outside waterproofing though and it would need to be reapplied afterwards. I went shopping for something suitable and found this NIKWAX product in my local motorcycle shop (Bikeworld). Would it be any good, lets find out?
I paid FULL retail for this, about €17.99, I have since seen this in lots of other places for an awful lot less!