try downloading the trial versions and compare.

PW4 is far more versitile. Because now you are not limited to using only full circle imaging.

Dave

It is true that PW 4.0 will stitch more types of panos. The 6+T+B stitching is great when using the 10.5mm lens. I am very impressed with this feature.

PW 3.01 will only stitch 2/3 shot panos but there are three features that are better than PW 4.0 for 2/3 shot panos

#1
Manual stitching in PW 3.01 allows you to see the seams while adjusting Yaw, Pitch and Roll. The seam will adjust in the windows as you adjust the parameters. This allows you to perfectly alighn the seams.

PW 4.0 has this feature removed. You can only adjust using the Center X,Y and radius. You must restitch afer each adjustment. Stitcing takes up to several minutes or longer for each adjustment. PW 4.0 has a new feature called "seam blending" but this does not allow you to make alighnment adjustments, only color blending of the seam.

#2
 PW 3.01 --- Stitched output has the seams correctly placed for touching up. The two seams are placed equadistant from each other at the center of the image.
 
PW 4.0 in 2 shot places one seam down the center and splits the other seam allowing it to be placed at the left and right edges so tha it can not be touched up unless the pano is converted to a cube, saved, imported and re-converted back to a spherical.

#3
PW 3.01 Manual stitching windows are large enough to see the seams properly.

PW 4.0 does not have manual stitching but does have a similar window called "seam blending" aside from #1 above these windows are only 10 pixels wide. They are so small I can't see the seams properly. Monitor 19 inch at 1280x1024

3 shot comparison is a little better

PW 3.01 perfectly distrubutes the seams in output to allow for touching up

PW 4.0 shows all 3 seams but they are shifted to the right almost too close the right edge but still workable.

PW 4.0 has no manual stitching. You must adjust Center x,y and Radius and restitch.
PW 3.01 does have manual stitching allowing quick and easy adjustents to the seam.

Below are links to 2 shot and 3 shot images stitched with both programs.
PW 3.01 2 shot: http://66.118.155.203/360/panoweaver/pw_301_2shot.jpg
Seams are properly places at center of image.

PW 3.01 3 shot : http://66.118.155.203/360/panoweaver/pw_301_3shot.jpg
Seams are properly placed and equidistant from each other...not too close the the left or right edge.

PW 4.0 2 shot: http://66.118.155.203/360/panoweaver/pw_40_2shot.jpg
The first seam is centered in the image. The second seam is split and placed at the left and right edge. There is no way to repair this area. You must convert to cube, save, import, reconvert.

PW 4.0 3 shot: http://66.118.155.203/360/panoweaver/pw_40_3shot.jpg
The seams are all visable but shifted to the right almost too close the the edge but still workable.

UPDATE: 6/14/05
Panoweaver has told me that PW 4.0 "uses different math" and so the stitch is in the middle as described. They state you have to convert to cube to touch up.....   :/

Manual stitching has been replaced in PW 4.0 with matching points. This method is more time cosuming that the PW 3.01 manual stitching. But PW 4.0 has a better algorythm as noted and can stitch more than 2/3 shot. It now supports the sigma 8mm  and nikon 10.5.

If you will be doing mostly 2 or 3 shot I think PW 3..01 is the best choice. If you will be doing 4 shot sigma or 6 shot 10.5mm PW 4.0 is needed. PW 4.0 does an awsome job of stitching 6 shot. Can't beat that, but when it comes to 2/3 shot I would go for PW 3.01

At the moment you

If I'm only going to be doing 3 shots (with FC-E9), is it worth $300 to buy 4.0 over 3.01?

In my opinion PW 3.01 is way better for stitching 2 or 3 shot. The manual stitching in PW 3.01 is very nice to have. It is a real pain in the butt to do matching points and restitch each time. Read the post above very carefully. The info is there.

You really should install both trial versions and try them out to see for yourself.

Gen. Lee

Hi webquest...

as I stated earlier... if unsure buy 3.01 and upgrade if needed. 3.01 is perfectly able to do good 3 image stiching and the differences have been well put forward by Gen Lee. I must admit to having a softspot for 3.01... however 4.0 has more features and will stich some images better then 3.01... however the reverse is also true. Therefore, having upgraded from 3.01, I have both. This way I'll use either for the given workflow/image output I'm hoping to generate.