Hundred Flowers is better than Guan Sheng Yuan in quality and higher in price than Guan Sheng Yuan. This high and low basically equalizes the overall cost performance of the two, so it's pretty much the same for anyone who buys it.
If you're not short on cash, I'd recommend buying the Hundred Flowers, but if you're not too well-off, you can buy the Kuan Sheng Yuan.
However, I'd recommend buying the Baihua one overall.