Hi Paolo,
We have a Fujitsu Celsius W410 i7-2600 with 6Gb of RAM and a Firepro v5800 graphics card.
We have had it for around 4 years with no issues with regards to hardware. We have replaced the hard drives (we do that every three years anyway), the graphics card and increased the RAM.
We have only replaced hardware to better meet our needs, not because of failure, as the workstations we have was an entry level one at the time.
It is very quiet, well built and I see no reason to replace it just yet. Although it is starting to show its age and more RAM may be required.
It has gone from Pro/e 2001 (don't ask ;-) ) on XP to Creo 3.0 M050 on Windows 7. Soon to be Windows 10.
We are a small company and are not restricted by IT departments (that's me) and are not bothered about official PTC supported platforms. In all the years I have been using Pro/E - Creo since 1998 on HPUX I have only ever had one issue where PTC would not support us due to non-supported hardware. Just to note that issue was still resolved by us within 24 hours anyway (memory fault). I could even get Pro/E 2001 to run on Windows 7 so I kinda know what I am doing, such a pain to do though.
I digress, TL;DR Our Fujitsu workstation is quiet, well built and is very reliable I forget it is there.
I hope this helps.
Miles