Have had the same problem with MR award availability. I will say that after trying 3 different times for 3 different properties recently, I decided that I would cancel my future business travel with 4 different Marriott properties, and in cancelling, I emailed the properties and advised that this was being cancelled strictly because of my inability to use my Reward points and as a protest against the capacity control/blackout policy.

Interestingly, I received a call the next day opening up the property that I had not been able to get a few days earlier.

I have to agree with the statement that generally, Marriott brands are more consistent for business travel than Starwood properties. But Starwood has Marriott beat badly when it comes to using the points - both in ease of award redemption and in number / variety of high end properties.

I don't think there is any comparison between Marriott and SPG in the higher end category (St Regis/W/Westin/Luxury Collection).

Just my opinion on the subject, but I think that with the exception of Starwood Preferred Guest, the hotel programs and airline programs should reset the worth of their points, limit the availability of points to actual stays or flights, but then open the programs so that their customers can actually use the points they earn - rather than this current state of affairs where points are extra-easy to come by, but almost impossible to use.