My coins-to-hold list:
1. ETH
2. BCC
3. BNB
4. XRP
5. WAVES

You need to carefully study the documentation of the project, in which you are going to invest. To study developers and administration. to find out in which projects they had previously participated. And assess the risks and prospects!

I don't think holding altcoins is dangerous and sometimes it even gives you a good amount of profit when holding it for long term. Although I'm not saying this in general but so far as I have observed, when it reaches a month or more the value of that certain altcoins mostly or most of the time increases its value but not all the time (also depends on the market).

I think NIO is a solid choice. It will be listed on Bitshares DEX very soon and should see a price increase because of that.
Also they have a working product already and they have a hard-working team.

It is true that we can not be sure of anything. Because the market always need correction. Bitcoin can also increase or decrease. The market must be safe and hold the price or raise prices.

ETC had almost low fluctuation in the market, I think it's hard for they to compete with the other altcoins. In addition ethereum was almost same interest like ETC that's why raising up of ETC to the market was affected too much.

The one thing that doesn't add up to me is that darkcoin is significantly higher than Monero still.  Comparing Monero to bit coin days.  There wasn't a precursor to bitcoin that tried to do the same thing in an inferior way that had a higher market cap.

I hope this coin will prove its legitimacy and soon we will see in coinmarketcap 

It seems a great project to consider. Can you guys tell me more about this project with whitepaper and clear roadmap.

I see more power in NEO, it is more young, but technology is great and auditory is huge (all china market). I would hold both, Neo and Ethereum, but at my sight NEO will give more profit for long term. In very very long term these two may have equal value.

I also expect an intermediate target of 0.001 btc, the Project develops, and the coin has organic growth. We have long been in the accumulation zone around 0.001. If this level is reached, then we will move to the top

Ethereum is a perfect coin for holding on a long-term basis. Trust the coin and the project. It seems everyone in the top is gaining value.

The coin is certainly good, but what are the facts for so much growth? x10 is quite a strong statement, is there any information, from which this growth is possible? I'm also thinking about investing in this coin.

I'm expecting a flash pump too but I think you need to have an extreme luck to catch it fast enough.

It can reach BTC value someday if more and more use cases of Ethereum like ICOs, cryptogams and etc will be implemented in the future while Bitcoin will stay slow developed one purpose coin. But that's very unlikely.

If bitcoin goes for another run then I am sure Altcoin will crash very hard again but then it will be a good opportunity to buy cheap altcoin !

It isn't dead. It is just moving up and down due to market fluctuations!

One needs to study well before investing money, only smart decisions may help to raise money.

From my side, it's a 50/50 I have taken a chance a transferred some of my coins from btc to eth, so its like yes I still do have some faith so keep going on with it.

Best Bitcoin hardware wallets are:

Ledger Nano S
TREZOR
KeepKey
Bitlox