I have the Givi E21 side cases, and I really like them. As stated by others, they're perfect for commuting, and good enough for long trips if you packed appropriately.
They're the narrowest out there (within a half inch) and the least expensive setup by a long ways ($300 to my door for the complete setup vs. $1000 or more for those "other" brands).
They're versatile too - you want larger cases? Order them from Givi, they'll snap right on your mounting brackets. Try that with Happy Trail or Jesse.
You got another bike with Givi racks on it? Stick your cases on that bike, they'll also snap right on. Versatlity & practicality at an all time high, with the Givis, as far as I am concerned.
DL650K5, Race Tech Forks, Scotts Stabilizer, SuperBrace, Staintune Exhaust, GSXR Calipers, Fastway EVO III Pegs, Givi Crash Bars, Motoagora Bellypan, TouraTech Rad Guard, Givi E21 / E41 Cases, Givi E52 Topcase, Cortech SuperMini Tankbag, Suzuki Euro Screen / Givi Touring Screen, Madstad Bracket, Kaoko Throttle Lock, Suzuki Heated Grips & Handguards, Dual PowerLet Outlets, Pat Walsh Dash Shelf, V1 Radar Locator, Garmin Zumo 550.