Inflow is a very good datacenter. I have visited their DC once (Austin, TX) and their monitoring room is impressive. As far as I know, Inflow is manned 24/7 so you will always find someone on the other end (instead of voice mail).
Inflow normally uses 2 or more carriers for redundancy. As far as DoS, you may want to inquire directly to them. I do not know about their financial strength, but the one I visited is cash-flow positive. I talked to their engineers when I was there and surely they know what they're doing. I would recommend them based on what I saw.