Briefly XRP had a market capital of over $2 billion more than Ethereum, they are swinging back and forth right now pushing each other in to #2 and #3 positions.
XRP has rocketed the last few days but can it last long enough to position itself as a long term #2 to Bitcoin?
That's not the case anymore. Ripple is already #3 and I believe it never will be #2, for there are other good coins like eth (already there), iota (I'm sure we'll see it there some time) and bch (not such a good coin, but it has quite a lot of admirers and sometimes advances up to #2 especially due to Koreans' love of it), which are probably better candidates for #2, since at least they adopt the main ideological points of cryptocurrencies.
XRP is doing great and perhaps even now is still a great time to buy it regardless to its position in marketcap list.