They're both very nice cars! No complaints.

The i4 is great because it looks like a regular car. It's literally just a 4 series grand coupe with an electric drivetrain. No gimmicks, no "the car needs to look futuristic" approach that so many manufacturers take with their EVs. The door handles are regular mechanical door handles.

The iX is... not exactly the opposite, but close enough. My understanding it that it was a concept car that BMW ended up releasing publicly. It's got an expensive electrochromic glass roof that you can switch between clear and frosted by pressing a button. It's got flush, electronic door handles. It's got a carbon fiber chassis. Things like that.

The iX is extremely comfortable for back seat passengers, as the back of the car is huge!

Everything the i4 can do, the iX can do at least a bit better. For example:

• i4 can do hands-free highway driving up to 40mph, whereas the iX does it up to 85mph.
• Both have options for parking and 360 cameras, but the cameras on the iX are noticeably higher resolution.
• i4 has air suspension for the back, whereas iX has air suspension for all four wheels.
• They're both great to drive, but the iX is smoother and quieter. The cabin is extremely quiet even at highway speeds.

The i4 is a lot cheaper though. I'm leasing both, and the i4 is less than half the price of the iX. I'm in the USA and we're paying $812/month plus tax for the iX, and $394/month plus tax for the i4, thanks to a combination of rebates, BMW loyalty discount (for the i4), and a 10% discount off MSRP.

We custom ordered the iX. It took a few months, but we could get exactly the options we wanted. It doesn't cost any extra to get a custom-built one compared to getting one from a dealer's lot.

Unfortunately, the iX has been discontinued in the USA. They cut off custom orders a few months ago, and dealers don't have many left. Rumor is that tariffs made it cost too much to import into the USA. The iX5 is supposed to replace it, but it's not coming out until next year.