I've a read about it in Silvershotz between the different devices, will summarize it for you.

Drum Scanners
Highest quality - very expensive

Dictated Film Scanners
High quality - good for regular scanners

Flatbed Scanners
Have come a long way - TPU (Transparency Units) can eb sued to scan film

Then there is a lot of talk about bit depth and resolution.

Top of the rang is Drum scanner no doubt about that but not within most of our budgets.

For resolution.
dictated film scanners are round the 4000-5000 DPI
flatbed scanners go over that these days with around 6400 DPI

For smaller film high resolution is important with medium format it's most likely over kill.
Over 4800 DPI you will most likely just enlarge the grain of the film.

Bit Depth
seems there isn't much of a deference there, all good scanners can scan at 16bit.

What's is best for you something you must figure out for yourself.
If you want I could scan the article for you?

Most primes have simple barrel-shaped hood, look at the DFA100mm, DA*200 & DA*300.
I believe they think it's the best design for prime lenses since they can precisely make it fit the coverage of the lens instead of the sensor we see with zooms. It's just a different way of doing things.

They probably went for the simple hood for the DA50-200 & DA55-300 because they're cheap and easier to make and work perfectly.

The only reason I can think of why the hood of the DA*55 is smaller is because the lens is smaller, if you would then reverse mount the hood for storage the hood would be longer then the lens.
Is that an acceptable explanation?

Chris knows a lot about scanning a lot of negative, he is the expert of the forum about this

Chris How long did it took you in the end, a good month if I remember correctly?

Strange the values shouldn't change in Manual mode besides when you press the green button, I don't even know an option in the menu that can enable something like that...

What happens when you uncheck the box under settings, you find it like this menu>custom menu and it's the first word of the list "settings" with a box behind it, when you uncheck it it will disable all your custom settings.
If that solves it you know the problem is in there.

How many negative do you want to convert, I think that's the main question which machine might be the best for you.

If it's just a couple you might want to use a normal scanner even, don't know how good they are but at least you can do more with it then convert negatives.

For the K10D, K200D & K-M it's between the ISO 100 & 200
K20D & K7 is a bit over the ISO200
K-X seems to have a base ISO close to the ISO400

If we must to believe the reviews.

Quite correct.
1/125 is fast shutter speed though and the sensor get noisy with long shutterspeed because it get warm. So it depends on how many photos you take and for how long, I wouldn't worry too much about this with normal photography only with long exposures of seconds.

There is no real dividing line in ISO, there is something called base ISO and it's the ISO where the sensor capture the most exposure range, with most sensor it's around ISO 200 and ISO 400.
And we would see noise at all ISO speeds to be honest but when it gets too much is a personal choice.
Most user would find ISO800 the max for most camera's although some would preform better and other worse.

For the rest, here take a look at this site, it might explain everything you want to know http://www.cambridgeincolour.com/tutorials/image-noise.htm

Andrew, from what I understand you use a 28mm for the shot of yours?
When I look at the photo it says 43mm and that's not correct because you're using a 28mm lens.

I'm saying this because the shake reduction needs to have the correct focal length to work properly or else it mgith even blur your photos because the focal length is off with 50%

Focal length is lens specific and does not change regardless what camera you use, a 100mm is 100mm on a mid-frame camera and on an APS-C sensor.
What change is how much the sensor/film capture about what the lens see and that change the angle of view or what most use the field of view.

How can you simulate how a lens will preform with a simple web program? I think I'm missing the point

Coatings are different though, at least for sure on the WR.
It's unknown what the Samsung less has or if it's the same as with the non WR pentax.