Pediatrician recommended formula switch - anyone been through this?

Our 3 month old has had some reflux issues and our pediatrician suggested switching from Similac Advance to Similac Alimentum (the hydrolyzed stuff). It's like triple the price. My wife is worried we're being oversold but the doc seemed pretty confident it would help.

Has anyone dealt with this? Did it actually make a difference or was it just an expensive experiment? We're considering trying it for a week or two but want to know what to expect before we dump $100+ on formula that might not work.