Power regenerators on pre / digital - any downsides?

Hi all,

I get the problems with driving power amps from mains regenerators, this can dull the sound if the unit can't provide enough power. I've had my sound utterly ruined by mains filters too, strangling my amps. 

So on to the question, is there any downside to regenerators for pre amps and digital kit, i.e. those units that don't draw much power? I see a lot of interest in power cables but I was thinking about fixing my mains. 

Thanks, Tim