PETG is just a bit easier to print with once you get settings dialed in. It isn't so cool-down sensitive and prone to warping as ABS, and doesn't have that 'breathing this shit will kill you' smell while it is printing. It also doesn't continue to outgas long after printing. PETG has good strength and flexibility and slightly better heat resistance, which is why I suspect CA told you it is better for printing things in the car.

I tend to agree with CA as well, for a first printer [for most people] it is better to get something that works and learn the basics of printing. Then use that knowledge to dive into a kit or a full-on DIY build. There are always exceptions, but most people are better off learning to drive a car first before attempting to build their first one from scratch.