I have both the 323 and the 626. While they are very similar I advise anyone to get the 626. The 323 has only 8 programs. 626 has 9 plus a, b, c , d, e and f programs. the first 8 programs are exactly the same on both machines and while on the 626 you have double the memory the first 8 programs have the exact same max decay as on the 323. You only take advantage of the extra memory on the 626 for the extra presets and on the extra presets you can actually have longer decays up to 20sec (only preset A does 20sec) or delays with almost infinite feedback. there are mono and stereo delays and delays with some panning variation.
On the delay programs they have fixed delays like 100, 120, 140ms etc. This varies with with the delay preset and the increments can be narrower or wider (weird amazing machine) Its difficult to describe how it sounds but a darker version of eventide blackhole with some delay is the closest thing I can think of. They have a fragile feeling in the hands and are very light. the inside looks simple and If something fails it should be simple to fix. I love it. They are rare machines ,specially the 626, very unique , look cool, and relatively affordable still today. In 2020 I paid for a 323, 1000e and a 626 in mint condition , 1500euro. Grab one now.