Yes and no. Good program and reasonably easy to get to status. At the same time, likely to disappear in the near future and there are a number of changes going on in it right now that are not incredibly customer-friendly. Still, it is probably the best *A program in Europe right now unless one flies a LOT of paid long-haul C/F fares.

For the OP, *S will not get you extra luggage or lounge access. And there is no alliance-wide complimentary upgrade scheme. Getting *S might not really get you what you are going for.