What car is that going into @avolve?
The VW is easier in that the original RCD/RNS units are essentially just a double din unit and don't integrate the AC controls so it's easy enough to just swap one out (with an appropriate CANBUS adaptor and face plate).
Do you already have a replacement AC control unit and mounting plate conversion thing in that picture?
Do you need an adaptor (like the CANBUS one needed for the VW)?
Assuming you have (or can get) both the above, the install might be as simple as plug and play if you're handy enough with trim removal tools. It's not nearly as daunting as it sounds.
We have two VWs and I've got a Pioneer AVIC in one and the stock RNS510 in the other. I keep looking at CarPlay but can't quite justify the cost for what you get since I've got nav/bluetooth/RVC in both cars already.
...but if I was in the market for a new head unit, I would be (and have been) tempted by one of the Android based units which support DAB+, which sadly means you miss out on CarPlay (last I looked), but get other fun stuff... like the ability to run Torque Pro and other nav apps. You can also have the unit itself connecting to the internet and doing your streaming stuff which maybe meets your needs (although sync might then be a concern).
Otherwise I'm a fan of Pioneer, although usually end up way up in their product line to get the combination of features I want. Sadly to get CarPlay & DAB+ you need to step up to their nav units which means it's $1,500+ for the head unit. My experience with built in NAV is mixed. While it works just fine, it tends to be waaay more out of date, updates are rare and it's missing basic features that sub $100 portable units have (like speed cameras/.school zone warning). Still it's handy that it just works all the time.