YouTube sub4sub, still a viable option?

What do you guys think about YouTube subscribers gained from sites like amf, ylh, l4l, and so on? My experience is that they get instantly removed (I see on analytics stuff like 50 subs added, 50 lost on the same day), but somehow I still managed to get like +100% subscribers from my original starting point (before the removal it was like 400%).
So, do you think is still a good option or not?

If they get added/removed,it doesn't matter.
They're shit subs and only spoil your subs-views ratio.

Well I have like 70 subs, having some more, even fake, can't hurt, right? I mean, who wants to subscribe to a little channel like that? having just 300 made some more real people join, but now I don't want to be in a rollercoaster where I get to 300, then 150, then 350, then 100 and so on, everyone will think that something fishy is going on