Both of those bikes are at the less expensive end of the classic bike spectrum - and sold when in new in quite large quantities and were quite popular. These days, neither of them are motorway blasters, but should handle back roads well enough. Don't pay too much, there are lots of these about, and the 350s are not as in demand as the 500s.
Both of them though, often in very high mileage condition, need to be examined thoroughly to make sure the oil is being fed adequately into the big end bearing through the timing side. Any skimping here in a rebuild can cause engine damage not too far down the road, so make sure the rebuilder has some knowledge of this. You don't say what years these are, but the magneto if it has one HAS to have been fully rebuilt, since old maggies are not renowned for reliability and will surely cause trouble otherwise. Check also for ful leaks, and that everything in the fuel system is in A1 condition. If it won't idle, reliably, this a sign it needs further work.
Remember too that everything in these old charmers can be rebuilt, it just may take cubic $$$ to get there.
And, like classic cars, may need a fair bit of fettling and tinkering to always give reliable service.
This is part of the fun of these. Hopethishelps.
