Lian-Li arent soley a high price manufacturer, the PC-7+ is a excelent case, that on build quality and capability blows a lot of more expensive cases out of the water. Thier more expensive cases are still comparable to others in their price bracket, but with the excelent design and finishing touches that Lian-Li put on all their cases.
And i'm not sure the problems with aluminium...... lighter by far than steel, and still very strong, and most gaming cases are moving towards it as a material. It's sure nice not to nearly give myself a hernia trying to heft a full tower around!
I like spending money on my computer, and the case is arguably one of the more important parts of the system (ive broken mobos before trying to sho-horn them into badly designed ones), and its the part you SEE. I dont spend my time looking at my case, and i dont go for windows and UV and LEDs ect, i prefer a case that is sleek and minimalist and tasteful, without compromising on cooling, quietness, or internal space and upgradeability.
In the end, a decent case will last you forever, as long as you dont drop it out the window or something stupid, so picking one that WILL last, and you will WANT to keep using makes sense.