No I didn't find it a heavy bag, and it can fit more than you might think. I did find the handles got in the way when carrying cross body and so I didn't keep mine, lots of people don't find this a problem though
+1!
It's definitely not a heavy bag and it's a little Tardis; you can fit a fair amount in there! I think there's a pic, somewhere on the forum, showing somebody's SBS with an astonishing amount of stuff inside!