Yes, the lagging has been absolutely terrible in recent weeks. I just canceled after 6 years as a result.
It actually started months ago, and they claimed at the time "it's only on some of our servers and we can't figure out which ones or why." (That certainly inspires a lot of confidence.) Apparently they are still spewing the same "explanation".
BUT, since I am still running it until my renewal date, I can tell you I didn't see the down spike you saw in the SPY yesterday.
This might be explained by my having been on one of their experimental "trade only" servers (which means they only deliver actual trades for charts, not all the bid/ask changes too). Switching to those servers (which you do by requesting it) did help with the delay in loading intraday charts, but it didn't help the data lag issue, and that's why I threw in the towel on them.
As for any promises they may be making about fixing the data lag issue, don't hold your breath. Several years ago when I was paying for their ECN book feature, it was ALWAYS messed up, and month after month went by with them always promising they were working on it. Never did it get better, and they more or less finally admitted they couldn't fix it for me.
Here's my strongest warning: Qcharts from Quote.com was a FANTASTIC service until Lycos got hold of them, then the data starting getting all messed up. They would promise they were working on a fix. It never came. I left them to go to esignal back in 2002 and was reasonably happy for the last 6 years (with the exception of the ECN book feature, which I had to give up on).
Guess what? Esignal has acquired qcharts and the data lags started when they began their efforts to consolidate their servers for esignal and qcharts. So whatever customer service reps tell you, there is absolutely no telling whether or even IF the problem will ever be fixed. The job of customer service reps in companies like this is to tell you whatever it takes to keep you hoping and, more importantly, paying the monthly fee.
Now I ask you: What kind of FOOLS sell market data to traders but are so INEPT as to introduce system changes without testing them before deploying them? I have simply had it with them.
One thing I find promising: IB's quotes never skipped a beat during all the volatility of the past several sessions while esignal was lagging badly and even going silent for minutes at a time.