Sovereign Silver works but isn't the greatest. The best commercial CS I've tried is Utopia. I was expecting to really like Meso-Silver but it was strangely ineffective for me. Utopia's still the best.
That said I haven't bought any in years. Ever since I bought a SilverGen and started making my own by the quart for pennies, it's taken care of my needs. Yes the Utopia is better ounce for ounce, but being able to use the cheap stuff more liberally without concern for cost ends up making it more effective for me than the best commercial CS.