I first found them when .pro went offline for about two weeks earlier in the year. I cannot remember if I read a post or googled it.
One difference I believe, and I will get confirmation on this, is this is a one-time fee. Whereas with .pro it is (if I read correctly) a yearly fee.
My analysis of this deal is that it is good but not great. So if something else comes up that would be better, we should vote this down and I'll resubmit it on another cycle. If we've got the available funds, then I feel we should vote it up as the exposure should be good. .online has more coins listed and I think looks and works better. In the short term, .pro is the better site due to market share, but I believe .online will be very highly regarded and could provide more exposure in the long run.
The way DASH handles issues with fluctuation in currency is this (using our coin and made up numbers). Let's say this proposal passes, then 312K BBP go to the address I control. If at that time BBP was up to 50 Sat, I would send the 12.5M Sat to .online and then be expected to do something "good" with the rest (my suggestion, and what I'd do is send the extra to the Orphan Fund address). If the price dropped to 30 Sat, I would be faced with one of two options. Eat the difference and fund it personally or ask for more funding in the next funding cycle to make up the difference. What I'd personally do is, provided I had the funds to do it, make up the difference and then ask for another round to make me whole.