after firmware update the startup times were noticeably better [...] connect directly by USB

That's a good tip, thank you. This will also remove the need for the Zoom driver then, I guess (which does not cause problems for me, but fewer drivers are always better).

H1 can use [NiMH rechargable batteries]

My user's manual says differently, but note that I have a different device (H4-N) too, could be different. They might have changed that since I bought it, too. Or maybe the manual is wrong, who knows. I've admittedly not tried.

With two AAs, my device allows you being in the bird park for an afternoon (recording not too much alltogether -- few seconds here, few seconds there, alltogether maybe 30-45 mins). Seems to me like recording and being in standby eats almost the same amount of battery (which I find stunning!). Since batteries aren't precisely cheap, I thought that I'd mention, to avoid a nasty surprise.

But if it actually works with NiMH rechargeables, even the better. No problem then, as you said :-)

recorder's shell/casing, which is plastic and "feels" weak to reviewers

My H4-N feels like a brick. Yes, it's mostly made of plastic, but it still feels like a brick. No worries there. And it looks like a taser...

Why not hold it in your hand? How would you suggest using it?

If you have a bit of tremor (like basically everyone has, to some extent), you can sometimes actually hear that in the recording! The same goes for moving the device and pressing buttons on the device.

It's usually no biggie if you concentrate and are cautious, but preferrably one would put the device on a tripod (standard camera tripod winding is on the bottom) or on a hard, stable surface (beam of wood, table, bird observation stand).

H1 can use [NiMH rechargable batteries]

My user's manual says differently, but note that I have a different device (H4-N) too, could be different. They might have changed that since I bought it, too. Or maybe the manual is wrong, who knows. I've admittedly not tried.

Odd. I think this is the official FAQ:

H1 FAQ - Can the H1 use nickel-metal hydride (NiMH) rechargeable batteries?
Answer: Yes, the H1 can use them. However, it cannot recharge batteries. Use a commercially-available charger to recharge batteries for use with the H1.

H4n FAQ - Can I use nickel-hydride (Ni-MH) rechargeable batteries in the H4n?

Answer: Yes. However, please note that the H4n does not have a function for charging the batteries.

You should therefore use a commercially available charger designed for the batteries you are using.

Also, to ensure that remaining battery capacity is indicated correctly by the H4n, set the "BATTERY TYPE" option in the "SYSTEM" menu to "Ni-NH".

For details, see page 128 of the Operation Manual.

If your manual says otherwise, you obviously taking a risk. It may be the same product, but an earlier version of that product. I'd check what page 128 in your manual says. If it's unrelated to NiMH batteries, then this FAQ might be for a later version.

Why not hold it in your hand? How would you suggest using it?

If you have a bit of tremor (like basically everyone has, to some extent), you can sometimes actually hear that in the recording! The same goes for moving the device and pressing buttons on the device.

It's usually no biggie if you concentrate and are cautious, but preferrably one would put the device on a tripod (standard camera tripod winding is on the bottom) or on a hard, stable surface (beam of wood, table, bird observation stand).

Thanks for that. I'm not sure exactly how I'll alleviate the shaking, and the tripod I'm getting is only about 4 inches - probably won't work in tall grass. But I'll see what can be done.

One more thing regarding accessories:

The question which windscreen you use is mostly an aesthetic one in this case.
Whatever you slip over the microphone(s) will muffle the sound somehow

Stands and holders can be very useful, the H2 has quite a bit of handling noise due to the plastic casing, but it came with a cheapo tripod and a holder that you can put in a microphone stand - they both do their jobs.

Note that the H2n ships with neither windscreen nor stands or holders. Again, don't know about the H1. Might be worth looking into!

So I've never used the H1, but I expect it to be a good tool as well - I'd just visit a local store and compare it with a few others in the price range.
Or get an H2 or H2n used, despite their plastic casing they're pretty sturdy. I've dropped mine a good dozen times and it's missing its card lid and has quite a few dings and dongs, still sounds like it did on day one.

Looks like you've already made up your mind and have gotten good information from everyone - But I just wanted to say that I have the Zoom H4. It's a little more expensive but I got a good deal on eBay for this one, used. The interface is awkward and clunky, eventually you'll get used to it, but that's the worst thing about it. It's a bit noisy to hold because the plastic isn't as solid as you would think, but I have the accessory stand and just use it on a mic stand if I record any ambiance. But you can definitely hear it in your recording when you're handling it. Never really used it for voice but it's solid as hell for everything else. Built in mics are great, phantom power is a huge plus if you want to throw a shotgun mic into it at a later time.

The H4-N is rather sensible to wind, too. Operating outdoors without the foam thingie that you can put over the microphones is entirely impossible, the slightest sigh of wind will be heard. With the foam thingie, it is kind of OK as long as no moderately strong wind blows.

google 'red head windshield h4n' or something like that.

Bought two of these a while back, really exceptional accessory. The guy was really nice too.