Well I've got all three of the Index books so far. They are scans of existing material that's been cleaned up is definitely not from the original sources. I suspect that the Index series are possibly due to GW scanning everything they've written/released for electronic archiving (I have no idea if this is what they're doing, it just seems a logical thing to archive) and they've had the idea to make some money from the task. The only book that looked blurry to me was some of the artwork on the Imperial Guard army lists but checking them against both WD and the 40k Compendium the Index versions have been cleaned up considerably, some of what they're scanning from is actually fairly poor quality that was ok back in the day but it's noticable now.
I disagree about the scattergun approach to what they're printing and the illogical contents. We're all very used to the order of what they're printing from existing sources and initially it makes it feel a bit disjointed when it's actually not. E.g. the Inquisitor Thrax story being a fair few pages into the Chaotica one when I'm used to it being right at the front of Slaves to Darkness. The contents are logical when you actually read the books (well they are to me). The books cover 40k as well as AT and Space Marine which was a nice surprise.
There are a couple of niggles in the books for me. As has been mentioned articles cut off mid way through. This is because GW are leaning more towards the fluff and not including full rules, you're not going to be use the Index books to build a RT army with all of the required rules. Personally I think they missed a trick with that! Also some artwork has had its orientation changed and has been cropped to take the re-orientation into account, the colour Blanche Mechanicus painting from RT being the most obvious, and I wasn't too impressed with the huge borders around the pages, especially on some of the colour double spreads.
Even so, for the dosh they're absolutely great imo and I'll be continuing to buy them as they release them. I do own everything they've printed so far but a lot of it exists across various sources as well as pages I cut from WD back in the day and they've been very nice to dip in and out of. At the end of the day I think it's great that GW have admitted that their games have history (I'm sure we all remember the days when they didn't) and are giving people new to the hobby the opportunity to experience what we did with some really classic material.
Edited to add: I reskimmed the Chaos book last night having posted this and I Will admit that pages 16 and 17 aren't brilliant but page 18 is very poorly reproduced.
