I had the R1 edition, which was pretty bad, picture wise - a lot of grain, and only a Mono 1.0 soundtrack. Also, the whole set of ten one-hour films were put onto two double-sided DVD's, making it a real pain to watch them in the correct order. Originally, that cost me about £55 to import, but I think has now been deleted.
The R2 editions, are available as "Dekalog 1-5" and "Dekalog 6-10". both being double-dvd presentations, but using single-sided discs instead! They aren't cheap, but do have some small amount of extras. They retail at about £24-99 per set, but you may be able to get some reduction on price via internet DVD companies. The picture quality is the best I've seen the series shown in, and the original was never great anyway, being made for Polish TV, back in the mid-eighties. I also think that you get a 2.0 Mono soundtrack as well, rather than just a 1.0 soundtrack.
The R3 version doesn't look too great, and bear in mind that:-
- the films are Polish, with English subtitles, but will also probably have
- Korean, Chinese and/or Japanese subtitles added onto the films as well, meaning you'll have two or three rows of subtitles. I don't think the translation is as good either, for the R3 edition. Ultimately, I'd go for the R2 versions, albeit at a price.