I have tried all the ice cream and frozen yogurt shops in Cambridge (and many in Somerville and Boston). Many of them are quite good, but there is no doubt the ice cream here is the best.
Toscanini's is hip and experimental with its flavors, and not every one of them is a total success, but most of them are truly fantastic.
The atmosphere is spare and (understandably) crowded. Prices are high as expected for ice cream in Cambridge.