To answer the question in OP; Both are basically the same thing by arch, but the FX8350 is faster just because it has higher clockspeed but at the cost of higher wattage too.
The FX8300 is at 95watt TDP at 3,3Ghz with 4,2Ghz boost clock, while the 8350 is at 125watt at 4Ghz also with 4,2Ghz boost clock.
Everything considered, personally I'd go with FX 8300 and pair it with some decent aftermarket cooling solution so that it can sustain its highest clock when needed all the time. I don't think AMD's old stock cooler could manage that.
But if it came with an AMD's Wraith cooler, all is well.