We have had excellent experience with Bornemann as well as with Flowserve Multiphase pumps (twin-screw type). Very reliable and can sure handle multiphase flow from wells to separation stations (they are designed just for that).
Our experience is with artificial lifting of extra-heavy oil, Progressing Cavity Pumps (PCPs) downhole and Multiphase pumps in the surface.
However, this arrangement may not be feasible in some cases. It makes sense if your wells are clusterized (grouped together in wellpads). The discharge manifold for all the downhole pumps in a cluster is the suction manifold for that cluster's multiphase pump.
Some ratings to give you an idea: downhole pumps are 150 to 170 hp and the multiphase surface pumps are 800 to 1200 hp. There is one multiphase pump for every 10 to 18 wells approx.(depends on wellpad total output).
The multiphase pumps not only carry the production to the separation station, they also lower the Delta-P across the downhole pumps (e.g. PCPs discharging into the multiphase pump suction).
However, multiphase pumps are not feasible in all production schemes. For instance, if your case involves a number of wells some distance from each other an using rod (donkey) pumps, then the idea of a multiphase pump may not be feasible. They are relatively expensive and it is not something that you would have "one per well".
May have more comments if you provide some details as to the type of field and production mechanisms involved.
Regards,
MS
MS