Haven’t used their borderless account but I live in NZ and get paid by a UK company into a UK account. I use them to bring all my money back to NZ and have nothing but good things to say about them. I usually have the cash in my NZ the next day but sometimes I’ve had it the same day, they’re really fast.
Yep, I used them so send money every month between EU countries and the money is available literally instantly, compared to 2-3 days for a regular bank transfer. The rates are better too. You can also lock your transfer rate for up to 24 hours, so if you think there's a chance there rate will be better the next day you can lock your transfer rate for a day - if it improves, just schedule another transfer. If it goes down, then send the one planned the day before. It's really good.
I haven't checked for the UK, but take a look at OFX if you can, I've found a notably better exchange rate from US to NZ when compared to Transferwise.
I got a borderless account about 4 months ago and I am happy with it. I use it to receive my salary in pounds, and I use the bank card to pay in pounds and euro in UK and France.
I choose to use this account instead because they let me open the account before I moved to UK and they sent me the bank card in France.
Still, I run into few minor problems: it's impossible to change the limitations of the card with the web-based interface, you need to use the android/ios app (which I don't have). Also, I have never been able to pay in Asda and Tesco by inserting the card (but contactless works). I never had any problems with other shop or hotel.
I've been using them for a while now. I have had no issues and everything works as they say it does. I use it to transfer money between bank accounts in various countries as well as their debit card for travel.