looking to buy a new custom built pc, anyone experience with the shop?

I can not help with the exact question, but having had computer shops for a long time, i can help choosing parts, if you are interested in building a PC.
In general, pre-built systems have become useless as they skimp a lot on power supply, motherboard, even cooler, so you might end up with a half-assed system costing 3000€ and performing as a 1000€ system.
Dell, HP, Asus, NZXT, etc are even worse as mostly you get a single stick of RAM on them, and that is frankly, criminal negligence as it limits performance a lot.
See Gamers Nexus on youtube.
For used ones, look for HP Z series or Lenovo P series, those were built like tanks.