I asked a similar question a few years back on the UK+Ireland forum here.

I have taken a Ryanair 6:50 flight a few times since then although not very recently (last time was over a year ago). My experience was that, while the queues can be long, they are fast moving. I had contemplated buying fast track the first time round but did not need it and been OK.

There is a risk so I would not take the risk is something important depended on it (eg: job interview, wedding or funeral, etc...) but, in ordinary circumstances, it is imo small enough for me to take it. You might have a different view if you are more risk averse than me.