what is the difference between OP_CHECKMULTISIG and OP_CHECKMULTISIGVERIFY
OP_CHECKMULTISIG, OP_CHECKSIG, OP_EQUAL all put true or false on the stack. This means you could use them with an OP_IF or similar, it doesn't have to immediately end execution if its false. OP_VERIFY will, as you quoted, mark the transaction as invalid of the top stack element isn't true, but you may not want to, you may want to perform some additional logic before that.