If you're planning on long term investment I'd rather invest in Litecoin. It's like a Bitcoin's little brother with faster & cheaper transaction!
And that's why for now it might not be such a good investment. I'm sure the price'll drop, we just have to wait. I was lucky to buy ltc for $20 and I'm still holding it
As for the OP, well, I've never likes stratis, because IMO it lacks innovation. It might be fine, but there's nothing special about it, just a compilation of main features of btc, eth + proof of stake. Litecoin, though, doesn't offer anything new as well, but I guess it is mostly used, because it's been around near btc for too long to be easily forgotten. Oh, and it did go through this one segwit improvement + Charlie Lee is still working on the coin. That's why I would choose ltc between these two.