The key here is it all depends on how much savings you've got. Most people I know have life savings of less than a year's salary, and don't own any assets. For them, it would probably make sense to invest a lot, >50%, because they could make the money back by living very economically for a few years.
If you have a million dollars in the bank, then it would be pretty dumb to invest >50% of it IMO, I would say no more than 15%, more like 5%
This is such bad advice. You're advising the guy who doesn't have money to invest a lot of it, and the guy who has tons to invest a little.
This is actually pretty standard (smart) advice. You want to have a risky investment when you are young, and move to a safer investment as you get closer to retirement.
However to say that Bitcoin is as "safe", at this time, as dollars is just totally not true. There would have to be some sort of worldwide strife to destroy the dollar's value.
What about US tax revenue reaching a point where it can't cover US interest on debt, at which point US has to either cut billions of dollars of spending instantly, or drastically increase inflation, which will increase interest on debt, which will increase the amount they have to inflate, over and over?
On the other hand with a relatively small amount of fiat money someone could 51% attack BTC and destroy it.
A 51% attack can't destroy bitcoin. In a catastrophic worst case scenario, it could make it stop working for a day or two until the attacker is neutralized. It will tank the price temporarily, but will retain all of its other functionality, and will just increase trust even more by demonstrating that it can survive.
Armory sucks for me. Upgrading it erased my Bitcoin Core installation. The bootstrap still doesn't work after several tries. Now I have a week long download ahead of me. I will wait until there is a lite version.
Armory detects if your bitcoind doesn't have the blockchain, and downloads it over torrent for you automatically. Takes about an hour.
1. My intuition tells me BTC and any PoW coin will slowly decline as mining becomes more centralized and harder, people will steadily migrate to alternative crypto's that don't use a PoW model.
Only MINERS will move to alternative cryptos. Not users, businesses, or developers. Besides, who cares about miners? People can't print USD at home, and don't avoid it because only a handful of people are able to print it.
(no, I'm nowhere near any of those ages) 
