EIS/SEIS- are they popular?

[R33FAL]

Are these fairly common investment routes for tax efficient investing? So far have taken a look at EIS fund providers (that do the work for you but take a 20% profit cut) or the ones where you do the analysis yourself (Seedrs) but wondering what success rates are like on both? I am amazed how some EIS fund managers have been around for a decade but only have 2-3 exits to their names....