I've got a cash ISA with them, best rate I could find. Been good so far although as has been pointed out verification is a bit onerous, but I suppose it keeps the scammers off. Don't rely on it for withdrawals at weekends though, during the week I have found it pretty instant but once past Friday evening I've had to wait until Monday for it to show up in my current account.
If you’re thinking of opening up with them have a look for ‘financial interest’ on yourube and other investment channels (don’t necessarily take their advice) they have affiliate links that often get you a bonus £50 for signing up through their links.
I use trading 212 for cash isa and invest engine for investments and moneybox for lifetime S&S isa.