One tradition with Sony smartphones is that they are nearly always overpriced at launch. Sony's latest flagship, the 2016 Xperia XZ, was no exception - it started at a whopping $699. Although the official MSRP has been marked down to $649 since then, you can now get it from Amazon for just $449.99.
I would say that the Xperia XZ is definitely a good phone at this price - it has a Snapdragon 820 CPU, 5.2" 1080p display, 3GB of RAM, and expandable storage. It also has some features rare in flagships these days, like expandable storage and Dual SIM support. In addition, the XZ packs IP65/68 water resistance, but Sony warns that the phone's USB port should be completely dry before attempting to charge. The phone shipped with Android 6.0 Marshmallow, but has since been updated to 7.0 Nougat.
As for customization, the XZ isn't a bad option. TWRP is available for it, as well as a few custom ROMs - but unfortunately not official LineageOS builds. If you want a gorgeous-looking phone, this isn't a bad choice at all. You can get it from the source link below, but at least for now, only the Blue color is discounted.