My first impressions have been :
a) Couldn't find an active AA PNR
b) Couldn't find allowable routing for a given fare, expedia was better
c) All fields have to be manually input: no logical suggestions

d) *** deleted ***
e) Quirks

have to be manually input - ITA is far, far better
1) Seeing in a glance loads for all flights in a route ^
2) Looks nice, simple, fast and professional ^
3) Fare info is nice but then it's available at travelocity
4) *** added *** Excellent customer service - answers in a short period of time ^
Perhaps other have had better luck, but so far I'm far from impressed. The sheer fact that I can't fully rely on its info is bad news, be it PNR or routing rules - making it a paid service then I'd expect something more robust.
Or perhaps I'm used to free and reliable services - who knows.
I'd suggest it, nevertheless, for a beginner as it's a good start. I'll keep giving it a try but if it continues this way I'll just give up, within the trial period...