Was searching for a thread comparing WGT and TWO until I found this one. All the other threads have been locked because of undue controversies. 
Hope we can keep this thread nice & civil. (It needs to be said the previous 2 posts are months old, and especially TWO has greatly evolved since then.)
Earlier tonight I managed to complete my very first TWO round, a 93 at Pebble Beach. 
I'm blown away: the game ran very smoothly from start to finish (in full-screen mode, too), and the graphics seemed much improved compared to the previous Beta cycle. I could never see ball flight previously, and Wolf Creek looked pretty shabby. Now, the same courses look glorious, despite my notebook being 3 years old and not capable of running the game using the best graphics settings. TWO's images are, of course, computer-generated, and can't compete with the clarity of WGT's HD photographs, but they are of astounding quality anyway.
What an experience it is, to see incoming ocean waves at the famous Pebble Beach, hole 7! What a thrill it is to see a flock of birds fly over your head as you tee off on hole 18! Those kinds of experiences will never be offered here on WGT.com, due to the static nature of photographs. It was such a thrill to play there I (inadvertently) sent at least half a dozen balls into the ocean to celebrate the occasion; it's a good thing I didn't have to buy them. 
The range of camera views is much wider on TWO. You can choose any set of pin positions, green speeds, fairway speeds, tees, winds. There's a wide array of keyboard shortcuts: you can move your aim around just by pressing the arrow keys on your keyboard! That's definitely the better way to do it for me, instead of messing around with the mouse all the time. You can activate the shot meter with the spacebar, too. And the shot meter is smooth as silk, no hiccups whatsoever. Multiplayer is now possible in TWO, too, although I haven't tried it in practice yet.
None of this worked for me in TWO's previous Beta cycle. I couldn't complete a single round back then. It looks like they improved the game tremendously over the last few weeks. I have likewise improved my 3-year-old notebook: I bought a new hard-drive for it, a Seagate with 7200rpm. It makes the notebook run faster and nearly noiselessly; could the new hard-drive, at my end, have contributed to the game becoming playable for me? I wouldn't know the answer to this.
The game did not seem excessively easy to play for me; witness my premier round of 93 (using the easiest settings), although I was more or less shooting haphazardly just to check if I could complete all 18 holes.
All in all, WGT now has some stiff competition in TWO. The other game already offers 5 full stroke-play courses, with the sixth course to be released in days' time.
True, the two games follow completely different business models. WGT will always be free to play with basic equipment, whereas TWO will be subscription-based. Judging by today's experience with TWO, however, I'd be willing to pay up to $10 per month for playing TWO.