That could be why the headroom was too low
Indeed, I'm 1m93 (6'4") and I specifically ordered without the sunroof since the headroom would have suffered a lot. 5'8" shouldn't be an issue though?
Anyway - my take on choosing for a Giulia - but not having received it yet (I get it next week).
I've driven quite a few cars, including a rental A4 for a few months. I also owned an Alfa 147, and before I got this, I was actually not that into cars. Back-then I compared it to other hatchback alternatives back-then (BMW/Audi/VW/Ford/...) - and up until the test-drive - I never even considered the Alfa as a serious option. Was the 147 perfect? Far from, but driving it, was loads of fun, although it was a FWD car and actual handling was only ok-ish. The 1-series lost out mainly due to it's very cramped interior, and in the end I was happy it did. Initially I had some doubts about reliability, but over the 10 years I owned it, driving 350k km's - I've had very few issues, nothing really out of the ordinary until the end when the gearbox gave up (also a bit my fault, chiptuned diesel, simply couldn't handle the extra torque in the long run). Overall I was a lot happier with that car reliability-wise than a lease VW Golf I drove for a while, which had more than it's fair share of gremlins. This car made me take German reliability with a large grain of salt, you can always have bad luck.
When looking at the new car now, the Giulia was my first choice, but I did look into alternatives. The A4 however was never really an option for me, having driven one for a few months, I thought it was bland and was nothing more than a device to carry me from point A to B. If that's what you want - go for the A4. It's undeniable that the tech is a lot better, and the interior build is probably better, but the styling was nothing I could get excited about. Other than that it just worked. Personally for me, I could not see this as an alternative for the Giulia. I also looked into the Kia Stinger, which is actually pretty impressive, but there's just something about the look I can't get used to. The 2 and 3-series were also on the radar, but again being a tall guy, BMW's "driver focussed cockpit" feels very claustrophobic, and not something I see myself driving for longer periods of time. The Giulia's interior just felt right, it's driving experience was one of the best, and while the tech is a bit behind, it has Apple Carplay, which is what I'll be using 95% of the time.
The choice is very personal, just go and have a test-drive. For me - that was the moment I decided I wanted the 147, I still remember the moment it convinced me. I had high expectations from the Giulia before the first test-drive after reading a lot of good stuff, and the initial drive was a bit disappointing because the dealer only had the oh-so-underpowered 136bhp diesel available at the time. After that I test-drove a few others and at last the dealer got a 2L petrol for me to test-drive, which pretty much sealed the deal for me.