It's not about the ads
Yes, I got my ello invitation recently and there are a *lot* of FB users I know currently jumping ship.
The reason has little to do with ads though, and here perhaps ello is slightly barking up the wrong tree. Most sensible users have adblock enabled anyway, so the intrusion from adverts is pretty small.
Certainly there have been many disgruntled users seeing their reach dropping off a cliff since FB decided to find ways to force them to pay for extended reach, but that's also been an annoyance rather than a reason to switch.
It's the intrusion into how users can portray themselves on the system that's really at the root of the exodus. My business concerns performers of many types, and they seldom want to use their real names in a public place. When Google tried the same trick with G+, they had a similar backlash. They've now removed that restriction, and I've seen a similar move by performers to try G+, as well as ello.
The thing ello currently has going for it over G+ is that it's simple, but that simplicity is based on very limited functionality, which is also it's weakness. Many users are already complaining that they can't actually do very much on ello.
My own web site is my primary way of staying in contact with performers, managing cast lists, media, etc. and my business only makes use of social networks for inbound marketing. As such, I'm not too bothered which social network they all end up using.
But I can tell you they are really unhappy with FB. They don't much like the G+ interface and find ello a bit sparse on features, so the jury is very much out on where they will choose to go, but they are actively looking at ways to leave FB, so it's just a matter of time before they do.