That is a 2014 Mini, more info here
Technical specifications for the Mac mini "Core i5" 2.6 (Late 2014). Dates sold, processor type, memory info, hard drive details, price and more.
everymac.com
I have the next step up, with the 2.8ghz i5 and 1tb Fusion Drive. The 480gb SSD is a nice upgrade and that machine should perform OK for "everyday" tasks. But it is basically a used computer and has no warranty from Apple. The 2014 Mini's get very little love around here, that was not a very good year for the Mini. But it is still a viable choice IMO. The RAM cannot be upgraded on the 2014 after purchase, it is soldered down.
I would also give some consideration to buying an Apple-refurbished 2018 Mini, you can get the entry level i5 model for about $600, although those only have 128gb SSD's. I think the refurbs with 256gb SSD's go for about $680. This is a much faster computer with newer ports and lots of other advantages. It will also have a full one-year Apple warranty and is eligible for AppleCare. IMO, a much better investment if you can afford it.
You have to be patient if you want an Apple refurb. More often than not, there won't be any on their site. But just keep checking frequently throughout the day. Eventually a whole bunch of different models will appear. Then, within a day they'll all be gone. So be prepared to buy immediately when you find what you want. Took me over a month, but I got the one I wanted. It is possible to upgrade RAM yourself on the 2018 Mini (although this is not officially supported by Apple)
Save up to 15% on a refurbished Mac. Tested and certified by Apple including a 1-year warranty. Free delivery and returns.
www.apple.com
Regarding moving files, not quite sure what you are asking. You can turn on file sharing on the G5 and connect the two computers with an ethernet cable. You could then just drag the files you want over using the finder. You could also use an external drive to transfer files. I had a G5, but it is long gone, so not sure about software compatibility. With Intel Macs, you could use a Time Machine backup or Carbon Copy Clone disk to migrate your old files, but this probably doesn't work with a computer that old.