I voted Parsons because he's a more accurate shooter, more efficient, and his max deal would be a bit cheaper. His injuries, defense and athleticism are concerns.
DeRozen is a superior defender, more durable, has intense work ethic, an Allstar, and close friends with multiple Blazers. His higher max deal, poor 3pt percentage and iso ball are concerns.
I'd be very excited for either player. They are two of the top free agents. Either has risk and both have negatives in their game so it makes for an interesting question. Both are far superior to the production we're getting from the last few guys in our rotation. I'd rather overpay on a legit proven starter as these guys are than overpay multiple lesser bench players as some advocate with our own free agents. Add one of these guys and we let whoever gets the most overpaid from our free agents walk.