I'm thinking of buying an Acer desktop on-line from the UK.
As I understand it, if there's an issue you have to call Acer support, who don't have a very good reputation.
With that said, most PC companies seem to have a bad customer care rep, eg. Dell.
If you run the search option in this forum you should find previous discussions on this subuject. Check out the charges for ringing their helpline also.
I have an Acer and I love it. Only small problem I have had with it was that the AC Adapter packed in after 16 months. I went online and had a replacement in the post 48 hours later from the UK. It cost about €40 including postage.
I can't comment in Acer support, because I never needed it. Both my PCs (desktop and laptop) are Acers, and I have had no problems with them. Decent build quality.