I'd looked into using services for bidding on Japanese auction sites going back in time, but they all wanted the money upfront before bidding - however seeing a mention of Buyee's alt approach in a YT video in mid-January then decided to give them a go.
Clearly the gods were smiling, as this coincided with a lot for a set of Japanese Duran Duran Fan Club material that I'd been searching for for years (inc a load of bits that I didn't know existed, as information is sparse) - & have kept on buying since... ...building up packages over each 30 day holding period, as combining postage to the UK is far more economical.
So, on the plus side, I've gotten a load of memorabilia over the last few months that either never shows up on the likes of eBay or at significantly cheaper prices all in, than either eBay or the few Japanese stores that particularly cater for the international market... ...& everything sent has turned up exactly as expected & really well re-packaged - though I have paid for extra packaging on the combined packages.
On the neutral side, there was a bit of a learning curve - where I foolishly started off by getting protective packaging on the lots as opposed to waiting until the end - spending more money than I should have done.
(& there was a lot which didn't arrive to the warehouse, but Buyee refunded that very quickly when I contacted them after the 14 day period - & clearly isn't their fault)
On the negative, the 3 things that I would pick out are -
1.If the auction states that the buyer pays for postage (within Japan), you're not told by Buyee how much that cost until you arrange for the package to be sent internationally - which is problematic for budgeting.
(I now have a good idea what the extra packaging, international shipping & customs fees will be - but not knowing if you've built up £50 or £100 or...??? of domestic postage within Japanese is problematic)
2. Whilst Buyee have had some offers on their fees during the time I've used them, it's uneconomical to buy *very* low value lots - as, esp when there's no offers available, the set fees can end up being far more than the item.
(though on the plus side you're still paying the same fee on expensive lots)
3. &, whilst I can completely appreciate that there are some sellers who refuse to deal with the likes of Buyee - & hence you can't bid on some items... ...whilst a handful of others you have to ask Buyee if they'll allow ... ...they have some weird blanket bans that can't even be asked about - so, for example, I can't buy any historical concert tickets on Mercari in the "Tickets > musics > Overseas artist" category - where I'm guessing they are blocking them all on the basis that they 'might' be for upcoming concerts where there could be issues with reselling.
All of that said though, once you get to know the quirks then, overall, it's a really great service - &, whilst there's some limitations, I wouldn't hesitate to reccomed them (& have done so on a Duran forum).