I know this site has a lot of positive reviews, so maybe I'm the outlier, but given my experience, I personally suspect those are fake reviews. So I wanted to share a real review to maybe help somebody out.
I needed to unlock an iPhone 12 mini that I own outright but can't be unlocked for a few months because my carrier is a jerk. (A review for another day, perhaps.) I was taking it abroad and wanted to put a SIM card that would work overseas into the phone. I read up on paying somebody to do it and everybody said be wary, but I knew I'd have to throw some money at this issue regardless, so I figured I'd give it a shot. Since directunlocks.com has such good reviews, I figured I'd be safe. If you want a TL; DR, my phone still isn't unlocked (2+ months later), but I want to detail 3 specific issues in case you're swayed by all of the positive reviews.
1) As has been stated in other reviews, they charge you first for checking to see whether your phone can be unlocked. As has also been stated in other reviews, that's information you can get elsewhere for free. My main caveat is that part of the reason I went with directunlocks.com is that they were only $28, and if I were going to lose some money at least that was less money than I would lose elsewhere. Yeah, after they check whether it can be unlocked, they charge you another $42 to unlock it. So it's $70, which is more expensive than anywhere else I looked at.
2) They give you a status tracker to show when you can expect your phone to be unlocked. Mine was ahead of schedule, which was great since I was due to be leaving the country 3 weeks after I started the unlock process. Except it stalled out at 99% and said that the unlock was "imminent." I emailed them after 24 hours to ask what was going on (I literally quoted The Princess Bride saying they obviously didn't know what the word "imminent" meant) and to get an ETA. They emailed back that they were chasing this unlock and I could check the tracker to see where it was (see pic). Except the tracker sat at imminent for the remainder of the time I dealt with this company. And when I emailed them back to tell them that I needed an ETA to make backup plans as necessary and that the tracker was not useful, I got nothing from them ever again. So do not expect customer service to be helpful.
3) On the job tracker page, there's a button that will supposedly let you refund yourself after 30 days if the phone isn't unlocked. Since they failed to unlock my phone before I left, I ended up buying a new one and figured I'd use the "refund yourself" button once the 30-day period had ended. Except, surprise, when I checked the page once the 30-day period was up, the button had disappeared. At this point I emailed them that if they didn't refund me in 24 hours, I'd dispute the charge with my credit card company (since they didn't provide me with the service they'd charged for). I then got a response saying that they'd refund me. A few hours later I got another email from them saying that my phone had been unlocked, and if I paid $42 (unclear whether this was the $42 that, to their credit, they did actually refund me or yet another $42, as I didn't pay it), the unlock would be sent over WiFi. So expect them to not hold up their end of the bargain and to need to threaten them to get anything done.
I will add a minor caveat: since I didn't pay them the $42, I don't know whether it would have actually unlocked my iPhone. I can get my carrier to unlock it soon, and I'd already bought another one to take on the trip, so I didn't need to get it unlocked by somebody else by that point. It's possible they really would have sent the unlock for me. So if you're out of options and are okay with a) waiting, b) threatening, and c) potentially still having your money stolen, this company might work. I bet $28 on it and lost, so I'd say don't go for it, but if you really have no other options, it might work out for you.