My new favorite synthetic brush is the RazoRock Hive MokaSoft High Density Shaving Brush. It's $20 when it's not on sale, and it not only lathers and splays great, I also think it's quite an attractive brush. I have not had good luck with the Simpsons synthetics (Chubby, Duke and Trafalgar), so I've been reluctant to try some of the other expensive synthetics like the Muhle STF and Omega EVO. I'd be interested in hearing from anyone who has used one of those and also has the RazoRock Hive to see how they compare.