I brougnt my 14 world over that I has used 1st for the no spoon, then later for all of the other achievements, including Irone Throne 3 and the 20mil green chips. So it was fairly easy adding on the .15 science (I had already tore down science as Tech Maniac was done). I really like my new science setup as it can pass packs from one lab to the next. Changing steam was no worries as my base was 100% solar and what little steam I had was only backup that hadn't turned on in ages anyways. Past that the pumps I had to shut off heavy cracking when lube got low had to be re-arranged a little. Everything else in the base was still working as normal.

All that being said, I love the new features of 15. Free blueprints and import/export. Ctrl-clicking, Logistics window, etc etc... love it all :)

Just started looking at nuclear and it would be awesome in a new world, but like I said I'm already all solar (5k panels and counting). Nonetheless I'm still gonna play with nuclear in this world if anything to learn it.