I've used Swype extensively (the newer one that's designed for tapping also), and Swiftkey and SmartkeyboardPro.
If you're Swyping, yeah that's one thing. But what do you do when you hand your phone to another person? The tapping isn't superb, but it's getting there. Furthermore, Swype seems to break completely with autocomplete browsers like Opera.
Swiftkey is a good tapping keyboard, but it's limited. I don't know why the numbers are oriented in a phonepad manner. The options are far too limited. Is it good? Is it far better than the stock Android keyboard? Yeah. However, the benefit of Swiftkey is to give great prediction, although the devs seemed to get the hint that it's better to also work with good correction. If your'e a fast typer, you're not even gonna have time to read the predictions of the next word. By the time your brain registers, you've already typed half the next word. So what's the point? I've never used the prediction on Swiftkey. And if I do, the time I take to read the options and pick the word that I want to use next, I can already type the next word. It's not faster. This is just a gimmick. It's like Google Instant. If you know what you're searching for, by the time Google Instant processes half your query, you've typed 2 more words. By the time you read the instant snapshot and want to click on one of hte results, Google Instant processes the new words you just typed on since its previous "instant search" and you lose what you just saw.
I went to Smart Keyboard Pro and I never looked back. I've been HUGE on tapping keyboards, and I've used HTC_IME for over a year. SmartKeyboard Pro offers just as many features, and is excellent as a tapping keyboard.
My only complaint is that the Shift button goes to caps instead of lower case on the first tap unlike on the iPhone.... I find this weird because a bunch of skins on SmartKeyboard mimic the iPhone or HTC, where both keyboards go to lower case when you press shift on the first word....