I don't have much experience with altcoins and in fact some of my investments in altcoins have failed - mostly new altcoins.  What I can notice is:
- Many altcoins and high competition.  That makes it more difficult for investors to determine the potential of the project. 
- Rugpull, scam and virtual altcoin (fake trading volume, dead project).
- Investing in altcoins especially new projects really takes longer. 

That may be my excuse for my bad skills but I obviously concede altcoins are a very good piece of cake for a handful of profits.