Last I heard was that the 170 was not very well supported. What support there is only exists in recent kernels, and is probably not very well tested yet. You may well have an uphill battle trying to get this machine to work. let alone to work well.
I has worked fine for me for a year and I just did a test debian install with rc2 some time ago. It has compiled kernels, ran weekly debian unstable update etc with 1 strange hang in last year so I think this model 170 is not the problem.
If I get some time I will test with normal SS-5/70 too but I expect it to behave similarly.
-- Meelis Roos (mroos@linux.ee)