New player with a couple of questions

[Rangoon]

I finally picked this sim up through Steam. I also have SH4+expansion. I'm debating playing through SH3 a bit first, then SH4 and by then SH5 will be out. I've been scouring the forums/wiki's about this sim and now need to get serious about playing.

Is SH3 worth it? Or is SH4 just as good/better and therefore a better use of time?

Also...if I do start with SH3, is the general consensus that all one needs is the GWX 3.0 mod? Or are there others to consider instead? Or others to use in concert with GWX?

Thanks! Just need to get rolling here and wanted to check in with some experts.

Edit: I should add that while OLC is fascinating, I don't think I'll be ready to manually compute everything for a while...