Ok, after much frustration with the funky way Cisco implements policy-maps and policing on the 3750 I stumbled upon the rate-limit command and want to know if there is a difference in what I am doing.
Basically I have a 3X3750 stack. I want to police traffic on a guest vlan down to 1Mbs. When configuring policing I have found that you have to do the policing in a child policy-map and the only way to do a match that is legal is by input-interface. So the first attempt was to add gi1/0/1-gi3/0/12 but it says they are mismatched ports even though the switches are exactly the same. Then I was able to do multiple classes and add the policing under each class(3 classes for 3 switches matching the interfaces for each switch). This took but did not seem to police the bandwidth, viewing the vlan interface policy-map it showed match-all on the classes so I am guessing that may be why it was failing to match, although I am not sure, and there was no way to change it to match any.
To make a long story short either you have to be very creative or just lucky to get policies to work in this instance.
So while looking for stats on the vln interface a came across rate-limit stats and went to the interface and aplied a rate-limit directly on the vlan interface. It took and I am in the process of testing it now.
Now for the question, in this instance I just want to police trafic to 1 Mbs and I do not need to set dscp values for outgoing packets and such. Is there a reason not to use rate-limit here?