Yeah, I thought (in the vid I watched) that AMP1 sounded pretty valvey to me.
I think the vid I saw is the one on this page:
http://www.bluguitar.com/english/AMP1.html(I'm at work, can't check).
Near the end, he takes the guitar lead and speaker lead and sticks them in his fave Marshall and then swaps back to the AMP1 (all in real-time, didn't notice a cut) - there was a difference, but I wouldn't have said a valves vs tranny difference myself.
In the same vid he does the Record Out and Headphone socket instead of mic'd speaker - he seemed almost apologetic about that and moved on quite quickly! But he was right, it's a usable sound for recording. I just think the THR does that side of it better - but it does it by allowing you to pick and choose which impulse response files you want to use (btw, I didn't like the default choices in the THR - I changed it to use the speaker sims of its own speakers!). As far as I can make out, the AMP1 has one speaker simulator and that's it - but the amp tones on the side of the box would make a bit of difference, maybe enough to please me.
I'm actually wondering now, but can't check at the moment, whether he'd just been demoing the "turn the side tone all the way up to get a biting rather than round sound" before he switched to demoing the Record Out into a desk? If that's the case, that was NOT showing the Record Out in its best light for someone like me!!
Anyhoo... If I didn't have the THR already, I'd be in a bit of a quandary - which would suit me best?

The AMP1 seems to beat the THR on an "issue" I've seen argued about elsewhere - the THR has no patches or saved settings. Before you play with it this does seem "omigod how do I get back to that gorgeous sound I had two hours ago?" - but after a few days it doesn't seem to matter, you seem to just know how to get back to it.
Price-wise, it looks like it falls halfway between a THR and a THR Dual. I got the THR Dual for cheaper than the list price of the AMP1
I'm a bit biased - I LOVE my THR, but I'm suddenly worried I've got the wrong one now!

However, it looks to me like I'd be real happy with either AMP1 or THR, depending on what I wanted to use it for and how I wanted to approach using it.
(And, in fact, just typing in here during my lunch break leaves me wanting to get home and switch the THR on again!! After watching that vid last night, I was up in my studio fiddling with the THR settings and room placement, inspired by what I could hear from the AMP1. It only took me 5 minutes - including some furniture moving(!) - to satisfy myself that a) I could get where he was going on his demo if I wanted to and b) I really need to restring my favourite strat!!)