Verizon’s first 4G LTE smartphone is big, bad, and blazing fast. I’ve had one in my hands for a few days now, and while it’s too soon to give a full-on review of the device, I have formed a few first impressions.

There’s no getting around ThunderBolt’s size, which is roughly on par with HTC’s other 4G devices, Evo 4G for Sprint and Inspire 4G for AT&T, though Inspire is noticeably thinner and lighter. Compared to Verizon’s iPhone 4, Thunderbolt is .25-inches longer, .3-inches wider, and a whopping .15-inches thicker than Apple’s smartphone. The ThunderBolt also weighs in at 5.78 ounces, which is nearly a full ounce heavier than iPhone 4. That’s not to say that ThunderBolt’s size is a deal-breaker, but rather to point out the obvious- this ain’t no lightweight Droid.

That said, ThunderBolt also feels like a tank, build-quality wise. Nothing about holding this phone in my hand said, “squeaky,” “creaky,” or “flimsy.” Rather, it feels like holding a very tightly crafted piece of machinery, a feeling only echoed by how difficult it is to pry the battery cover off the back of the thing. Rounded corners, grippy surfaces, and a brushed metal kickstand that opens and shuts with a firm, reassuring snap: ThunderBolt is the Sherman Tank to Samsung’s lightweight plastic Galaxy S phones.

Battery life has so far been fine – not noticeably stellar, but not noticeably horrid either. I’ll test that in a more proper way next week. The 4.3-inch WVGA display is bright, responsive, and easy to type on, and the tweaks HTC made to their Sense system have only improved on what’s basically the only version of Android I personally enjoy using. Yes, I can hear some of you disagreeing with me. Vehemently.

There’s also no getting around ThunderBolt’s speed. Single core or not, this thing feels fast when I use it. Swipes register, voice actions are heard, photos zoom, and webpages render quickly. The Web page thing is due in equal parts to the device’s 1GHz Snapdragon processor and Verizon’s 4G LTE network, which Thunderbolt is equipped to take advantage of. Note that LTE is not yet available in many/most parts of Verizon’s coverage map. Note as well that it is lit up here in Oakland, CA, and it’s been screaming. I did some speed tests Wednesday using ThunderBolt as a Wi-Fi hotspot and averaged between 8 and 9 Mbps down, 3.5 or so up, and latency under 60 ms. In lay terms that’s roughly twice as fast as Sprint’s WiMax and 4-5x what AT&T’s HSPA+ was pulling. The Android app is literally unusable on Thunderbolt – the app’s developers have said so, and promised that an fix/update is on the way.

On the down side, Wi-Fi Hotspot mode has been failing me all day today. I’m able to turn it out and connect a laptop to ThunderBolt, but then the 4G connect starts a vicious cycle of dropping and reconnecting to the point that the network is rendered unusable. I haven’t had any issues with the network using Thunderbolt on its own, and have put in an email to Verizon asking for help with the situation. I’ll report back next week.

Meantime, have any of you plunked down your hard earned credit cards for a ThunderBolt? How’re you liking ’em so far?