[f-nsp] mstp disable vs no spanning-tree

[Steven Raymond]

What is the practical difference between:

1) 
mstp disable ethe 1/1/12


2)
switch(config)#sh run int e1/1/12
interface ethernet 1/1/12
no spanning-tree


?

#1 leaves the interface in permanent blocking state.  According to Brocade tac guy, he says that no traffic except BPDUs are forwarded on this interface with this command.

#2 I believe ceases sending or receiving BPDUs on the interface, and leaves it in a permanent forwarding state.


If my facts about #1 are correct, what may be a useful application of this command?  When would you usefully want to exchange nothing but BPDUs until manually changed?

What would be the best practice for my ports connecting to customer's L2 switches, with the goal of isolating & preventing spanning-tree traffic exchange?  

In what situations would you choose between "stp-protect", vs "no spanning-tree", vs "stp-bpdu-guard" ?

Thanks!