When the keyword is very popular and under 15 ccTLDs are available in the world for that keyword ( including .jp, .hk and other extensions restricted like .al or expensive like .nr or .
pr ) then i doubt can find any decent .com alternatives, almost any good domain is bought and parked, even keyword1, 2, 3 , 10, 14, 100, 1000, 5000, 10000, 100000 and the keyword is not in english! In this conditions the keyword.gs domain is almost perfect.
.GS cannot be restricted in SERPs in my opinion because the island is not populated. Probably has or should have the same authority like any .me, .in or .tv. (other geographically unrestricted extensions).