I have both of the Shun water stones (300/1000 and 1000/6000). They are not bad per se, just overpriced for what you get. Shun doesn't make them. They are made by someone else for them (which is true of most knife companies who sell a branded water stone.) In fact, when comparing them side by side, it is clear that the same company did not make both stones. The sizes, composition, and even the rubber base holder are all different. I bought them at about the same time from a major Shun retailer so no question about their authenticity.
Both benefited from use of a flattening plate before initial use to get a good working surface. They are also a bit undersized at a little over 7.25" x2.5", versus the 8" x 3" size that is more typical of full-sized water stones.
I would suggest either the Suehiro Cerax Combo 1K/3K or the Imanishi Two Sided 1K/6K Stone for about $55 each over either of the two Shun stones that run about $80 each.
For that matter, there are decent King combo water stones that are probably similar to the Shuns for a lower price, if you want to shop around.
That is not to say the Shun stones suck. They don't. They work, and you can sharpen your knives with them. They are typical short-soakers, about 10 - 15 mins is enough, and take about 2 days to a week to fully dry out again after use. The 1000/6000 is an interesting stone. It is *almost* splash and go, and is not really thirsty. 5 minute soak, and ready to go. The 1000 side is a rather aggressive and fast cutter (which is not a bad thing). Not much mud. The 6K side seems a bit coarser than I expect for 6K, maybe more like 3k-4k to me. No mud at all. Also, fully dry in a couple of days.
The 300/1k is a different beast. Soak for 15 mins, a bit thirstier when using, muddier, took almost a full week to dry out after use. It also feels like a different binder. Not quite the same size, and a different rubber base. All of which combine to make me think it's from a completely different maker.
Why did I buy them, you may ask? I was curious about the brand, and I got an excellent deal on them due to seasonal sales promotions a while back and living near an outlet store for a big retailer. I think I got them close to dealer cost. I would NOT have paid the normal retail price for those stones!