The picture is certainly much cloudier with hotels. (I don't MS for hotel points - I prefer to MS Barclay arrival for a big discount on the best available price at the hotel I actually want to stay at.)
For airfare, if you use miles for the same or equivalent trips to what you would buy (I do - cheapest coach option and/or cheapest miles option for 4 pax), and you churn so that much or most of your MS is meeting min spending requirements, you are getting at least 6-8 miles/points per dollar.
I have yet to have a trip average under 2 cents per mile value compared to the lowest cost coach flight. So I average $60-$80 in airfare per VR purchased. It's not terrible...
Edit: and then I buy VRs with cashback cards while I'm there, so my 3.95 has been covered even if all the programs ceased to exist tomorrow.