What's everybody's thoughts on chip tuning box

Is it worth it pros and cons

Or better to map car

That depends on what you mean by a chip tuning box.... if you mean one of those things from Fleabay with some colourful leds then it's worthless. But a handheld unit from Laird, Bluefin, PumaSpeed etc is basically a remap in a box you can add or remove at your leisure

As Stu says, there are boxes and boxes and a lot of "tat" about which has been exposed as a con with wires and lights etc, as mentioned.

In the earlier days of electronic tuning, there were some well respected names particularly in the VW diesel world that stood up to scrutiny in testing. Basically the box was a secondary computer which overrode/modified the signal from the original ECU. 

Use has declined with the ease of remaps via the OBD port directly or via a Bluefin type device. Also one of the draws was that, when unplugged for service etc, the use of the device was undetectable. I believe that's no longer the case and most systems will flag that the factory set parameters have been tampered with at some time which may be discovered if investigating for warranty purposes, etc.

A name I remember was Tunit, which still seems to be around though whether it's still the same outfit I'm not sure: https://tunit.com/

Another name that springs to mind is DTUK: https://www.diesel-performance.co.uk/

There are plenty of test videos on YouTube etc and have a search for any of interest to get user feedback on owner forums like this one.