To bad you can't open the link... The short version is pretty simple: somebody is trying to link a couple of services together and atomicwallet is one of them. There have been some accusations floating around against some of the services the poster is trying to link together.
It's not conclusive proof, so i wouldn't call them a scam right away... I'd just advice to be carefull.
When you pick a wallet, these are the options from safest to unsafest... There might be some discussion about which of the top-4 wallets is the most secure, but if you pick one of the top-4 you *should* be secure enough:
- [very secure]An airgapped installation of a recent version of bitcoin core, non-HD on a clean *NIX OS (or windows if you know what you're doing). Do think about your backup strategy tough!
- [very secure]An airgapped installation of electrum or bitcoin core HD on a clean *NIX OS (or windows if you know what you're doing)
- [very secure]A well-known hardware wallet (trezor and ledger pop to mind)
- [very secure]A properly generated paper wallet (it's not that easy to generate a paper wallet in the right way)
- [reasonable secure]A wellknow, opensource desktop wallet on a CLEAN PC (virusscanner, firewall, updates,...). I prefer *NIX as OS: electrum (warning: a lot of phising versions are floating around), bitcoin core, armory, knots. It's safe to say that in my honest opinion, wallets like atomicwallet are NOT falling in this category...
- [unsecure]online wallets, exchange wallets, casino wallets
If you're downloading wallet software, it's always a good idear to check the signatures. For example: lately it seems a lot of phising sites looking like electrum.org popped up, and several people downloaded a fake wallet and lost funds. Since you're working with open source wallets, it's not that hard for an attacker to edit the sourcecode and influence the RNG or install a phone-home function, then recompile the wallet and distribute their infected wallet that looks 100% like a legit one... The only thing you can do is keep checking where you download your wallet and keep checking signatures.
In your case, it might be a good idear to look at ledger and trezor, for about ~$100 you can purchase a hardware wallet that should protect you against most attack vectors... An added bonus is that they usually support several (alt)coins, altough i doubt your specific portfolio will be 100% supported by one hardware wallet.