I mostly trade the forex pairs, gold, and the spreads have been fairly standard but sometimes I experience an increase in volatility during active trading sessions which is a regular downside with this trade.
Also, the execution speed is really good and I seldom have to complain about slippage, But sometimes the spreads increases suddenly, which may not be favorable for a few trades. It is not a devastating factor but somethings one could recall the feeling as he or she trades during periods of high fluctuations.