There are quite a few threads from members on the SBFtech site, but I have only read a few of them. I understand that there is power to gain for a boosted engine beyond a very mild boost.
The vacuum pumps seem to work the best, but it isn't clear whether the OEM type air pumps are long lived enough to be worth it. The belt driven kind obviously have the installation issue to deal with. The purpose built pumps are all very expensive, and the electric would be the simplest to add.
I gather that the typical header evacuation systems only produce 1-3psi of vacuum, not that much compared to the 9-15psi+ of the pump systems. The engine has to be very much sealed from all leaks to generate any vacuum, almost all engines leak(air) normally. I suggest avoiding the header type, those rarely work on the street, and only in ideal conditions, normally aspirated and perfectly installed. They have a lot of trouble getting them to work right.
I'm leaning to the OEM pump system, the Lightning air pumps seems to be the most common, lowest priced to do. They don't last forever, but it sounds like it could be reasonable for most street vehicles.