I've been using it to track my food since November. I use the mobile app and desktop version. The database is everything. Far and away the biggest database. I like being able to scan barcodes with my phone to save screen tapping.
I'm a low carber, and so I totally ignore their goal numbers, just use their tracking. I would like to be able to export the data into my own spreadsheet, which they don't seem to have. But MFP exchanges data both ways with my Bodymedia Fit activity tracker (calories burned from BMF, calories eaten from MFP), and BMF then can export the nutrient numbers.