Microsoft support is really awful. Basically, if you need it regularly, you just pay for resident engineers who can bypass the wall between the product groups and you. I’ve had nothing but great experiences with those guys.
Otherwise, especially if there’s a broader problem, they play lots of games with SLAs, etc.
TAMs tend to be a bandaid organizational sign that support-as-normal sucks and isn't sufficient to get the job done (ie fix everything that breaks and isn't self-serve).