Personally, since I don't mind flying coach and I can often find cheap tickets to locations, the hotel points wind up being more valuable in terms or redemption.

For example, based on what I just found on DL.com and MR.com, I can fly to AMS for $800. Assuming I've taken a bump and have a $400 voucher (usually have one or two on deck), I can fly for $400. The hotel is going to be $340/night, and those don't go on sale all the time like flight tickets.

Another example: ATL-SFO, flight $328 r/t, but hotel is $359/night (JW). I'll likely get a free UG, so there is no need to buy F. Clearly, the hotel points are going to be worth more in this instance.

Another consideration: When work sends me to Hawaii, I don't need anything towards the flight. If I want to stay there an extra week, the Marriott points take care of that.

That's why I don't even bother with the DL Amex card but do use the Marriott Visa.