i personally own ripple and golem. why? i believe in their vision, BUT realize they're both very speculative. depending on who you talk to, some say you're crazy to buy them, others will say you're crazy not to. at the low price, it's not necessarily an expensive investment... but it's high risk, high reward. in addition, i balance out my holdings by owning BTC, ETH, DCR (decred) - alt's i (and others) look at as a bit more stable. my approach is to stay diversified. i would not recommend buying ETH at current prices. buy on dips, and sell high. ETH could move higher, but i imagine it will take time and will most likely dip before doing so.

when you look at the marketcap, it's determined by shares outstanding = to share price. ripple and golem have a huge # of tokens compared to other alt's.