Too many preferences here but the truth is that lots of traders are trading ETH (with a volume of 70,000BTC within 24h only in poloniex), then DASH, ZEC and XMR. These are some of the top altcoins that are in the top of 2017. I only check the ETH price for the last 7 days and it's surprising how much has been increased and I hope that many people have made a huge profit since I didn't invested in ETH in the past unfortunately.
You are right, these are the most traded coins on the crypto market recently. On the other hand, their recent growth isn't anythin special in current circumstances. If you look on graphs of other alts, you'll see that almost all of them pumped at least a bit, some of them quite massively with +1000% growth and you could make a lot more profit on them than on ETH or other big alts.
What I want to say is that to diverse your trading also to some smaller alts isn't anything wrong and it can make you even more profit than to stay with only the big ones. Of course, you still have to follow the main rule - do some research before you invest your money into something.
