From a basic look at both websites, here are some differences:

Resource Builder includes an icon editor and support Unicode. With the 64% DC member discount, it costs $17.82 for a single user licence which can be used for commercial purposes.

Resource Tuner does not support Unicode and requires the purchase of a separate icon editor (eg. AWIcons Pro, which they also sell). With the 50% DC member discount on Resource Tuner, it costs $34.98 for a business licence (which allows commercial use), coupled with $60 for an AWIcons Pro business licence. Therefore, it costs $94.98 for a similar solution to Resource Builder.

Neither solution seems to support 64-bit exe/resource files.

So, on the surface Resource builder seems the better solution as it supports Unicode and costs a whopping $77.16 less.

I would also like to be able to re-edit text boxes once created.

Just tried SSC 2.09.10 beta to do scrolling capture of the file list of a Directory Opus lister window and, while it captured it successfully, the gap between some files is slightly too big. This appears to be at set intervals down the file listing so I assume the grab is done so many lines each time which are then appended together to give the complete listing. It's where they are appended together that the gap is slightly bigger.

I can post a screengrab if you don't understand what I'm talkling about :)