For general use MS Office 2011 is as good as any, plus it maximises compatibility with non-Mac users. Easily available for free via a certain Scandinavian torrent download site. Includes Word, Excel, the dreaded Powerpoint and Outlook etc. For website work, Adobe's Dreamweaver is very good indeed ...

In my experience, you have to plug your iPad etc. in to sync. I think there is a Wi-Fi option, as long as you are on the same network as your main Mac. Never used it, though.

Chronosync is quite good. I use it to sync my work files between my iMac and MacBook Pro. https://www.econtechnologies.com . Officially it's not free, but, well you know.

But if you just want to copy stuff from your main Mac, why not just drag and drop?

I use Carbon Copy Cloner. It runs once a day, and basically clones your HD. Handy. http://www.bombich.com/