Everybody else is saying great things about it, but I just could never manage to get good results out of it, probably as a result of me not devoting enough time to learn to master it.
Yea, my attempts with the Realviz trial version were not encouraging. There's is probably no clear winner here. Each program will have its strengths and weaknesses but to fully evaluate any program and find out what it's really capable of requires a lot of time and experimentation. I'm not prepared to spend that time.
One gets used to a particular interface. An unfamiliar way of doing things can so easily be seen as inherently awkward and cumbersome; a bit like a Mac owner switching to a PC for the first time, or vice versa
Whenever I've tried other stitching programs which might seem to be more powerfull than IA, or are claimed to be, I've always got the impression of great awkwardness in the method of execution; for example, trying to align a semi transparent overlap and peering at the screen to see if one image needs a little bit more rotation for a perfect alignment when it's difficult to be sure if it's perfectly aligned or not.
What I like about Image Assembler, apart from its very good fully automatic processes, is the easy way one can bring up consecutive pairs of images on the screen and zoom in on just the area where a particular pair of flags are, having positioned them approximately first. It's even possible to place the flags on two matching individual pixels if that's the degree of accuracy that's required.
I also like the way IA can force or align stitched images in a row (if you ticked the box in the 'options' window). Some stitching programs give a resulting image with great bulbous circular edges which have to be cropped, thus wasting up to a third of the image. The new version of IA has improved upon this feature. The 13 images of my 1.1GB stitch referred to earlier were taken about 6 years ago. The camera was not perfectly level and after stitching reduced size scans using the earlier version of IA, there was an unavoidable stepping effect at the top and bottom of the panorama, each image from left to right being a step lower than the previous one. Cropping the final stitch to a rectangle for printing resulted in some waste, maybe 10 or 20% depending on how much additional sky I cloned in. This new version of IA succeeded in forcing all the images into an almost perfect rectangle. Instead of significant stepping, there's just a slight raggedness of the edge in a few places requiring very minimal cropping.
I'm very pleased with this new version. It's a significant upgrade.