I transitioned to MSR Autoflow from Sawyer, finding it a little more reliable with better flow rate. It's not dramatically different and I still think the Sawyer gravity system is viable.

NB Some source water conditions challenge gravity system (regardless of brand) making them a dubious choice without either effective prefilter or backflush ability. Visibly cloudy water and clear water with a lot of organics are the usual culprits. UV with prefilter can be a good alternative, although it's far more fussy.

Cheers,