It's not a matter of algo. You should probably know that by now. It's the added value the coin can offer.

Bitcoin ... a mainstream - everyone can compare or exchange BTC for USD/EUR
Litecoin .... the alternative, with sufficient capitalization
Darkcoin ... anonymity - as the added value
Vertcoin ... secureness against ASICS (albeit - you know - every Scrypt-N algo can be implemented in hardware).

So... What's Groestlcoin has to offer - besides weird name and YAHA (Yet another hash algo)

Resistability to ASICS? Guess not - as *every* algo, Groestl especially - can be implemented in hardware.

So think hard about the added value the coin can offer.