What the main difference between the the regular whey and the one with glutamine and is the extra price worth it?

Our isolate + glutamine product is further refined and has a higher percent protein (and corresponding BCAA amount), with less fat and carbohydrates.  Whether this is what you want really depends on your training regimen and fitness goals.  This product also contains L-glutamine, which means it is best suited for someone that is training regularly and needs to optimize their recovery from workouts. 
How much protein do you need? Protein Calculator