The Atoms are insanely power efficient and produce little heat. There are only a couple netbooks that run a celery, and they aren't really the big contenders (pardon the pun). 95% of them are Atom 1.7GHz/1.8GHz or VIA C7 1.7GHz. The atom performs better than the C7, as its newer and takes advantages of a number of improvements. The C7 (particularly in the 2133) can get damn hot. I think that was the big reason HP went with an aluminum case, its a nice heatsink
Unfortunately, the Atom hasn't shown up in the 'business class' netbooks like the 2133 yet. I'd try for an Atom if thats the only difference between models. The celery is the bottom of the pile in nearly all respects, and even managed to lose to the C7 in most benchmarks.
Hard drive wise, there was a lot of talk early on when the flash hard drives became available that they'd be far more power efficient. In theory, if the drive spends a lot more time idle than it does working, yes the solid state drives are a bit more efficient. In any application such as mapping where the drive is getting constantly hit, they draw about even. There is the advantage of (theoretically) better vibration and shock resistance, but I haven't seen a whole lot on this topic outside a few industry journals. I opted for a larger traditional hard drive so I could use it to empty my HD video camera and DSLR in mid chase if necessary.
As for visibility in daylight, this is a big beef with a lot of netbook owners. Backlight kills batteries fast, period. On my 2133 by going from max to min brightness, my battery life typically improves by about 15-20%. Some of the lower end netbooks will skimp in this department for the sake of the battery. A few like the 2133 and the Dell have gotten high marks for screen usability outside, so long as you crank the brightness all the way up. My 2133 has a 'brightview' screen which is positively gorgeous, but glare is a problem. There are anti-glare stick-on and 'bolt on' sheets that can cut down on that though.
I always advocate "try before you buy" with laptops, but doubly so with netbooks. Each has its quirks and trade-offs, and you have to be certain that particular model has trade-offs you can live with. I personally loath the eee PC keyboard and plastic, flimsy feel, and that's what drove me to the HP 2133. Somebody with smaller, more nimble hands who rarely types much probably won't mind the keyboard. I envy the eee PC's Atom processor and the sheer volume of cool accessories and hacks out there though.
There is a bit of a twist in the netbook market that buyers need to be aware of. You'll notice that nearly all are capped at 1GB of ram, and a 1.7 or 1.8GHz processor. This is because Microsoft is artificially manipulating the market by requiring these 'maximum capabilities' be met in order for manufacturers to continue offering XP. My 2133 supports 2GB of ram, and is one of the very few that does. This made a big performance difference (turned off the page file), but it meant that the laptop came with Vista, which is totally unusable. Nothing a quick re-install can't fix though.
