I recently got a mini at Walmart, I brought in on a recent 5 day backpack, I could not wait to get my Steripen Freedom back.
For the Sawyer:
Price (major check)/ease (major fail - it is awkward to fill and use and can get your hands cold)/quickness (fail for small quantities (1/2 a L) of water gathered, check for larger quantities)/effectiveness (neither got me sick, so equal)/number of gallons it can filter (I assume a similar life battery of the Steripen vs the inevitable clogging of the filter), /weight (comparable but I do usually carry less water with the steripen - see quickness)/design (it's neat in it's lightweight filter design, but so is the steripen for it's purpose)
So it comes down to personal preference, and the Sawyer Mini is worth a try but certainally not the end of thread IMHO