PensionBee are a relatively new player and there is no advice - the investment selection is what’s known as robo-advice. Pretty low costs, however other companies have tried it before and ended up going bust as the Model wasn’t profitable.
Should be fine for smaller pension pots ( values of 20-30k where it wouldn’t be viable to pay for advice) or where no at-retirement advice is needed. For anything larger (or anyone with more compex needs) then an experienced DIY investor or a half-decent IFA should be able to do a better job.
I tend to get concerned when the likes of PensionBee or Hargreaves advertise promoting transferring pensions without advice - you need to be confident of what you are giving up, and that there are no valuable guarantees or really well performing funds that you are giving up.