I would consider Austrian the better option. Serveral points why: firstly you will have a chance of career progression - especially with the collective labour agreement just signed last week. Dash FOs are now being trained on the Embraers even with possibilities to later join the longhaul fleet.
Also, since living in Hamburg is essential for you - dont forget about standby tickets.
AFAIK Austrian have quite good ID agreements, so it shouldnt be any problem to get home for you. Eurowings on the other hand... i stand to be corrected but at least according to ppjn they dont have any.
Furthermore, with LH aquiring all off-hub routes from airberlin later this year, the chances of eurowings basing their own 320s in HAM in the near future dont really seem to be too high..