742's are decent hunting rifles.
They are not designed to last super long, as the reciever wears and not much can be done about it. From new, they seem to last about 4000 rds from what I have researched, before they become completly inoperable. This will basically be a lifetime's worth for a typical hunter, but not very long for a target shooter or varmint blower-upper.
I have one in .308 and one in .30-06. I bought them in the last 3-4 years and paid about $250 each for them; both came with a spare mag and cheap scopes mounted.
I personally feel that the guys wanting $400 or so for a 742 must either be selling a mint condition rifle or they are out to lunch.
A used Browning BAR is a better rifle, period, but, assuming the 742 and the BAR are in the same condition, you're comparing a $250 rifle to a $700 rifle, so they are in totally different budget ranges.