I have quite the story regarding the DL4 mkII. I had one for about 2 years. It was great until it crapped out at a gig (right at the outset). I was quite used to having the DL4 tones and depended upon on them to a large degree. All lights were on and it was completely dysfunctional. I tried all the tricks - restoring to factory setting, firmware upgrade, etc. Nothing worked. Since it was beyond the warrantee period, I decided to buy another one - new (and you better believe I registered it immediately). Lo and behold, the new "silver" model died the same death. I use a Cioks DC7 power supply (9v, 600ma per outlet - way better than the Line 6 power supply) so that is not what the problem was. I contacted support and they had me send it in. They claimed the unit worked fine - the unit I sent did not work at all (same deal, no ability to reset, etc). I will see what I get when it arrives. But note: they refused to refund my money. Now I have 2 pedals I have zero trust in - basically paperweights. I bought a JHS Flight Delay to replace the DL4 - it's okay. But meanwhile I'm out about $600 due to Line 6 DL4 mkIIs.
Let this be a warning - I will never buy another Line 6 product....ever! I'm an experienced pro and I need dependable gear from responsible vendors. Line 6 no longer makes the cut.