The first release of Google's open-source simplex solver (which this tab dubs 'GooPLEX') appears to be a simple toy version of the simplex method for Linear Programs. GooPLEX appears to be missing all the basic ingredients of a practically viable solver such as the revised simplex method, dual simplex, sparse LU factorization, etc. The good news is that we finally have an open-source solver whose license (Apache) is actually useful in the real world.
COIN-OR has a dedicated team, and a fantastic repository of solvers and other OR stuff. Unfortunately, its licensing (CPL and now EPL) is still uncomfortably and frustratingly restrictive for companies to use commercially, and thereby also improve by contributing to it. Consequently, it is likely that COIN-OR is going to be popular mainly within the OR-academic bubble. Ironically, most OR/IE departments will already have GUROBI or CPLEX licenses and thus wont be dependent on such *PL license based LP/MIP solvers. We OR folks need to stop shooting ourselves in the foot.
The smartest course of action for IBM and the COIN-OR team is to do what Google did and make the COIN-OR available under Apache/BSD. On the other hand, one hopes Google's developers and the OR community will improve upon GooPLEX and make it a scalable product. Go Google, and welcome to the world of O.R!