Dash has the best possible wallet support as it works now out of box with Trezor (trezor.io) - HW wallet. You will be satisfied and your DASH safe. Only more secure (but impractical) option is cold paper wallet created on not-compromised computer.
To the Synereo - yes, huge potential as mentioned but project history and progress was so bad that they will have to deliver something really special to re-gain their reputation back. Frankly, I'm quite surprised you are even considering investing in AMPs but who knows - I will give it a second look.
I really have to buy a Trezor though, in the future. I see that they really have a lot of altcoin support.
I have already invested in AMP, and I am already in profit. So I could sell now for 30-50% profit, but instead I hold on to it, because after they launch, I think only the sky is the limit.
Think about it, a total decentralized social media. There is only Steemit and nothing else right now, and Synereo is not even a competitor, they have a totally different structure that we haven't seen before, a totally decentralized system with 2nd or even 3rd layer applications possible.
If they deliver, and we have no reason to believe they will not, then this has the potential to even replace Facebook.