So many of these people test final versions of their candidate distribution on their old machine. If it impresses them there, they'll try installing it on their production machine. But here they can run into problems, because the hardware might not be supported out of the box, making time-consuming tweaking necessary.
The solution:
- Decide that you are going to give a certain team of developers a chance of making the distribution work for you (be they Ubuntu or Fedora or whoever).
- In the run-up to the next release, try their public betas on your new computer, doing your normal work. Save often and keep backing up to another machine. (It's a good habit to get into anyway...)
- If bugs occur, report them, and follow up whether they are being resolved. Give all the relevant information that developers will need to find and fix the problem, i.e. describe the bug as accurately as possible. If possible, help with debugging!
- Meanwhile, keep your old machine productive so you don't endanger your work, your job etc. You can only devote so much time...
- Keep testing until the final release (i.e. install and test every new beta as soon as it is released) and beyond - some things may still need fixing in the first few weeks after release. It often happens.
- Enjoy a Linux distribution that you know will work on your new production machine!