What color is this 8000 your looking at? There have been several different 8000's over the years.
Early orange 8000p models had the largest carbs and the cylinders with the smallest combustion chambers. These traits are required to make good power. The yellow Deere 800v above would be an example of this design - high torque closed transfer port cylinder.
Next, along came the EPA...and the gray T1E cylinders were issued in place of the earlier designs. Echo has been very accommodating to the EPA, including building a several million dollar air pollution study lab in Illinois. The T1E cylinders had large combustion chambers, flat top pistons and loose squish to keep the oxides of nitrogen down. I think Echo realized that the T1E engines were heavy and slow, but they could not justify the expense of engineering a new 80cc saw in a market that is shrinking. Ask any saw dealer how many 50cc saws they sell vs 80cc models.
The most recent 8000 has a quad transfer port cylinder, factory pop-up style piston, combined with a hemi head combustion chamber with tight squish. Echo noticed their market share dwindling because of power concerns. The public was not interested in longevity and instead wanted power. The release of the cs-4400 followed by the cs-520 showed Echo that they could take some market share from HVA and Stihl. They went out and re-engineered the top end's for both the cs-670, now the 680, and the latest 8000 right around the time they released the 600p. If you follow their advertising, for the first time in their history, theyre talking about power. Its good to have this competition in the market place because it pushes all of the makers to produce better products.
Just a little long winded history behind the model your considering. The 8000 is built as well or better than most. All have closed port cylinders and scavenge through a windowed piston. All have a metal die cast gas tank/rear handle. All have metal side covers and the only real plastic is the top cover. I especially like that the 8000 will oil any bar length, and comes with a thumb pump standard should you need extra. Some parts prices are reasonable, for instance you can put one of these new piston and cylinder kits on an older T1E crankcase for around $150. Part number P050005320. Check any other manufacturer for a top end price and compare. OEM not aftermarket. Overall, a little heavier but once ported, amazing.
http://store.besttruckeq.com/p050005320.html