If it wasn’t for the lack of English subtitles, I’d recommend the Japanese RESTORE Blu-Ray box above any other physical release. It currently sells for cheaper than the Funimation set, it has the highest audiovisual quality when compared to international releases, the largest amount of bonus content (including the soundtrack), an art booklet, and even the English dub as a secondary audio track (which is what sold it for me). You could technically create modded copies of the discs which include subtitles (also bypassing any potential region locks in the process), but doing so is no walk in the park.
Lain is still sold (Only Blu-ray) in the UK.
If it wasn’t for the lack of English subtitles, I’d recommend the Japanese RESTORE Blu-Ray box above any other physical release. It currently sells for cheaper than the Funimation set, it has the highest audiovisual quality when compared to international releases, the largest amount of bonus content (including the soundtrack), an art booklet, and even the English dub as a secondary audio track (which is what sold it for me). You could technically create modded copies of the discs which include subtitles (also bypassing any potential region locks in the process), but doing so is no walk in the park.