I think I'm set on the TB unless the earliest adopters cry foul. I'm ready to get started. Yet if I were recommending objectively to someone else based on my research, I'd probably say the Bionic. Unless the battery for one of them turns out to suck so badly that it's just not practical or there's some other unknown flaw that a patch can't/won't fix, I think you could buy either without regret.
UI
A lot of people like HTC's Sense UI the best among the major makers' UIs. A lot of people hated at least the earlier versions of Motorola's Motoblur UI but I've seen some people say recently that newer versions on the current top models are not any real problem. I haven't played with them enough to appreciate that well enough yet.
Bootloader
As far as I know we expect Motorola to continue its plan of locking the bootloader. That's a dealbreaker for people who want to flash custom ROMs to their phone, but I saw a guy here the other day saying the Droid X had a locked bootloader yet people were flashing it somehow. If that's true and if we can expect the hackers to overcome the Bionic's locked bootloader, then that would be less of a demerit for this phone.
Dual Core vs. Single
Dual core Moto vs. single core HTC. Some say it doesn't really matter yet because the Android OS versions that are out now are not yet optimized to work with two cores. Others say it will definitely help anyway. I don't know but it's a point of comparison. Unless there's a disadvantage to having two cores, I'd say might as well have two - maybe they'll be useful in the future if they aren't now.
HDMI Out
Bionic has an HDMI out port for hooking up to your HDTV, Thunderbolt doesn't. If you would actually use that, there's a point for Moto.
Kickstand
Thunderbolt has a kickstand, which is a point if that seems like something you'd use.
FFC
Thunderbolt has a 1.3mp front facing camera while the Bionic has only VGA (0.3mp). If video calling is important to you, that would seem to be a significant difference.
Skype
Thunderbolt has Skype somehow baked into the operating system for whatever advantages that may offer. There was some talk a while back that this would actually be disabled upon release and enabled later. I don't know if that rumor is true or if it's still true at this point.
Online Dashboard Service
Some newer HTC phones can interact with a HTCSense.com, which does things like syncing contacts and SMS, remote locking and wiping, app recommendations and other phone management features and goodies. I heard that htcsense.com is baked into the newest version of Sense and so should work with any phone that has it, but a user on these boards supposedly got an email from HTC that said there were some problems with that on the TB right now and probably wouldn't be fixed before launch, but would eventually be fixed.
http://forum.androidcentral.com/htc-thunderbolt/53540-thunderbolt-htcsense-com.html. As with the rest of this, I can't confirm whether either thing is true.
Screen
The Bionic has a better screen at 540x960 than the Thunderbolt at 480x800 (but have you seen that TB screen in the video? Beautiful. It's hard to imagine that not being good enough. And different screen technologies have different advantages or problems)
Battery Juice
The Bionic has a 1930 mAh battery to the Thunderbolt's 1400mAh. That's substantial but we don't yet know how either phone makes use of those levels of juice in terms of power management. One rumor on the TB delay is that the battery was giving up the ghost too quickly. No actual confirmation of that as far as I know and I wouldn't expect them to ever admit that if it were true.
RAM
Thunderbolt has 768mb RAM to the Bionic's 512, but the Bionic's is desktop-grade DDR2 RAM for whatever benefits that might bring. I haven't found a good explanation of that yet. I'm guessing either will be fine.
Maximum Storage
Bionic has 16gb onboard while Thunderbolt has 8gb. Both can take a 32gb card so Bionic technically has the edge, but Thunderbolt has a 32gb card included. So if the phones are priced the same, you're getting a better deal on the TB, pricewise. Maybe you don't need more than 16. If not, maybe that's better for you. Or maybe you want/need that extra 8gb of space over the TB's max, making Bionic the winner.
Benchmarks
As we keep finding out, specs aren't everything. Sometimes better specs aren't implemented well for whatever reason. I can't remember if I've seen comparative performance benchmarks for these two phones. Google it. My money's on the Bionic.
Release Date
The TB will be out earlier (that's been the plan anyway).
Emotion, Branding, Rumor, Minor features
Given the above, if the two phones were out at the same time, I would have a hard time not favoring the Bionic. I think I have an irrational bias against Moto for all the moaning I've read about Motoblur. That stuff may or may not be accurate anymore or maybe it's just personal preference and I wouldn't have cared either way. So it's weird that I still want the HTC. I've wanted an HTC phone for a while but that may also be somewhat irrational and brand-based. I like a few of the minor features of Sense (flip the phone on its face for automatic silent mode, etc.) but those seem like things that could perhaps be replicated via apps or otherwise done without. HTCsense.com seems like a nice bonus too if it winds up working. I don't know if Moto has an answer to that or some close equivalent. On paper, at least, it looks like you can't really go wrong unless something above is a dealbreaker/dealmaker for you.
Facebook
Twitter
Instagram