Yes Acer has come a long way. There quality is certainly adequate and they offer great value. Could you link the unit you are looking at? Pentium Dual core are 64bit. They are Core 2 architecture, They are Core 2's with some L2 cache disabled. They are not 32bit Core Duo's, no way they are still selling Core Duo's. Cache is tricky to tell how much it affects performance. On some applications it makes zero difference on others depending on what amounts you are talking? Less than 15% at the same clocks. Generally to be noticeable short of a stop watch 15% to 20% is where it just starts to get noticeable.
Have a look at these comparisons.
The PDC is a 64bit and is C2D w/reduced L2. So don't stress it.