speed of VBA and Lisp

No, they are not the same. VBA is interpreted at runtime and is generally slower than VB. However, since VBA runs inside of Autocad there is less overhead when communicating with Autocad (VB on the other hand has to deal with interprocess communication). So depending on what is being done, VBA may be faster for the given task.
If you have a lot of intensive calculations and not a lot of interaction with autocad (ie. calls to any autocad object), then VB should be faster. If you have a lot of interaction with autocad then VBA will likely be faster. Generally I program in VBA but call an ActiveX DLL (written in VB and called from VBA) if I have something computationally extensive.
-Tim