My wife always kicks me when I order a vodka tonic with lime, and they ask me if I prefer a particular vodka.... I always rely, " How good is your tonic?" That's when I get the kick!!
Nine times out of ten, the bar tonic out of the multi-beverage dispenser will be flat and with blended flavors.
I believe it best to always order a drink with a premium mixer/tonic. JIMOHO.