Conclusion

With the PC-P50 Lian Li shows a good case which unfortunately has some problems. If we on the other hand look at the price it fits quite well into Lian Li's recent portfolio.

Compared with other cases from Lian Li the PC-P50 with its 6.6 kg isn't what you call a super lightweight but still if we compare it with other brands it is on an overall good level.
If you look at the manufacturing quality it is also good only the side panels don't fit as tight as you might expect it from Lian Li if you're familiar to their higher price cases. Regarding 5.25 inch drives, motherboard as well as the expansion cards Lian Li equipped the PC-P50 with very good features and also plenty of space around the different components. Quite a faulty design tough is the installation of the hard drives. Therefore Lian Li uses the right components but the arrangement is just suboptimal. If you want to exchange or add a hard drive whilst the power supply is already installed you wont be able to remove the carriage from the cage. You're forced to remove the power supply in order to add or exchange a hard drive.
Futhermore very practical is the fastening mechanism for expansion cards which couldn't be any better. It is simple and the cards are bolted to the case.

Overall it is quite difficult to recommend this product although it's a good case. The problem therefore are other cases in Lian Li's portfolio. For a bit more money you'll get a PC-9 which is one of the best Midi-Tower on the market and for a bit less you get a Lancool K62 whose design is nearly analogous but the chassis is made of steel. If you're looking for an aluminium Midi Tower but you do not want to spend CHF 200.- (est. EUR 132.-) you're can consider buying a PC-P50. 

The Lian Li PC-P50 can be bought at Digitec to a price of CHF 179.- (est. EUR 119.-).