I am putting in a Cisco 3750 as a core switch and have existing Dell 5424 & 5324 switches at the access level. I know some times incompatabilities in implementation of advanced features such as etherchannel can be different between vendors and disasterous to use. Does anyone have experience with these model combinations that they can share?
LACP has evolved these days to where it's a very interoperable standard. You should not have any difficulty configuring a LACP bundle, even in active mode, between the two switches that you describe.