Try to negotiate for the echo bag instead of hard case. I'm able to store a spare chain loop, tools, sharpening kit, quart of bar lube, a can of trufuel, and spare gloves. Enough all together to at least cover me for a few hours in woods. Didn't like the hardcase at all.
Biggest thing with the echo's is that they are so lean from the factory that they have so much torque left on the table. Make the dealer set it up right or do it yourself. A tach like a dealer would have makes it easy. Dealer would have the tool to remove plastic limiter caps, or a small drywall screw works also. That will be your issue with a HD saw for sure but might be an issue with the dealer too If they don't prep it right. That's the case for a lot of saws is the dealers not tuning them before sending them out. Good dealers will tune them on a tach, then in wood. Don't expect HD to do it.
I own an echo cs-600p (the 2nd gen with the rubber coated aluminum handle) and after removing the limiters on the carb screws and richening up the saw on a tach, it is a beast. With a sharp semi chisel that isn't a low kickback variant, it'll walk right through even orange oasiage or black locust. Have ran it alongside several XP model husky saws, dolmar saws, and a tuned stihl ms660; and it runs right with the best of them. Non ethanol gas was hit and miss on anything over 87 octane, so I pretty much stick with trufuel unless I'm cutting with buddies that have home brews of non-oxygenated race fuel mixed down to wround 96-97 octane and amsoil sabre. With good gas, I can usually run 2-3 hard hours on a quart of trufuel.
I've ran several top handle echo's and loved them just like the rear handle smaller echos. Have also ran several prosumer stihl and husky that the echo's cut circles around even running chain loops made from the same bulk.
Want to get a lot of power out of a small saw, hit up mastermind on arboristsite. An easier and cheaper option is a simple muffler mod with a retune. That will wake up most saws.