Would it be upgrading if I switch from Nikon D200 to D3100?

I currently have the Nikon D200, and since I've started becoming "more pro" than I was, I'm noticing little things about the older DSLR models. Like ISO performance at only 400… With the D200 you start to visibly notice noise.

I'm thinking about upgrading bodies. I bought my D200 off of Ebay about 2 years ago, with 12, 000 shutter clicks for $510.

I don't want to spend much more than that, so I was looking at the D3100 for $700.

My question is… Although it's a more "beginner" DSLR, with no top viewing panel, or QUAL, WB, ISO ring on top, is it a better camera than the D200? Sensor wise?

I do notice that the D3100 does NOT have an in-camera focus motor, but I'm comfortable with manual focus on some lens.

I understand that the D200 is more robust, but if i'm planning on upgrading in 2-3 years (which I will, do to rapid improvement on technology), then getting a few dings on the body should be fine, right?

What should I do?

Added (1). Yes, I understand the focus having to be manual on some lens.

But how are the sensors compared?
In terms of:
-ISO performance
-Sensor size (1.4x crop?)
-Etc.

No.

The upgrade would be buying a D300s

Your D200 is a professional grade APS-C sensored camera.

The D3100 is an entry level camera. Any AF lenses you have been using on your D200 would have to be manually focused using the D3100

Here is how the three sensors perform head to head

http://dxomark.com/...nd3)/Nikon

Here is an example of what an older D300 can do, shooting at 3200 ISO

If your real goal is to include shooting video, then the D3100 is able to 1) shoot Full HD (1080p) and auto-focus in the video mode

If you are going to make a move and are not ready for the D300s yet, maybe you'd like a used D300. I bought the D300 as soon as it came out on speculation. I was so happy with my D200 that I thought I'd run it until it died, but the lure of a CMOS sensor was tempting. Since they were in short supply, I figured I could always sell it if it wasn't that much of an improvement. Well, I'm still using the D300 as my No.1 body as it is miles ahead of the D200. (Sorry.) If you are not ready to spend "big bucks," look for a low mileage D300 and you will be quite pleased.

If you want a new camera, I think the next choice would be the new D7000, which some are saying is better for image quality that the D300s. The build quality is right up there, too, although the camea is a bit smaller. It's the upgrade from the D90 and the D90 is no slouch. In fact, maybe a used D90 would be a good move. There are a lot of people jumping ship to the D7000 right now…

As a third choice for a new body, I'd consider the D5000. I would not move so far down the line as the D3100, though.

Once you have had the features found on the D200, it would just be too hard to go down to using only one command dial that has to be used in combination with other buttons to make the same changes that you now make with only one dial. The D3100 and D5000 only have one command dial, but at least the D7000 and D90 have two.