I'm in the market for a 15"-ish laptop with Thunderbolt 3. The Dell Precision M5520 has been recommended to me, and a friend uses the Thinkpadd P50. I have a few specific questions that I cannot determine myself since there is no M5520 in physical distance: Some reviews I have seen say that the Dell 5520 ruined the keyboard and that it is really awful now. Can somebody confirm or deny this? I guess that was meant compared to the 5510? Are there more hardware difference between the P50 and the P51 than just the tiny difference in specs? Again I am thinking of keyboard, trackpad etc Are the CPUs on P50 and P51 soldered on? ECC memory would be a killer feature for me. I wonder whether I can buy an i7 equipped one and put in a Xeon? Any other laptops you would recommend that can use an external Thunderbolt box with a GPU? Maybe something with a mechanical keyboard? I am open to gaming laptops as long as they are robust. Is anybody here using these? I will use these under Linux, maybe FreeBSD. They seem to work fine according to what I have been told. Of course more information would be appreciated. My previous experience is much more positive with Dell laptops, all of my Thinkpads seem to die after some time (or at least some parts of them), or those who don't have so bad keyboards and trackpads (T400 I am looking at you) that I don't use them. I am aware that the P50 is a self-defense class brick, I consider it because ECC memory would be a killer feature for me. Thanks in advance.