Rebuild it or junk it?

Got a 94 mazda 626 V6 5spd model with 205k mi. the trans is starting to "kick" out the gears. 1st, 2nd, and 4th are fine, but 3rd is starting to kick out when accelerating and 5th does it too. if i hold the shifter in 3rd or 5th its fine but 5th makes a loud harsh grind sound when i hold the shifter there, sometimes in rapid succession (like a metallic crunch sound) someone said the syncro is busted then said the gear teeth are wore off, i dont know please help.