Not as good as nerds say it is, and not as good as the original, but still pretty good.
As you might have guessed, I hate escorting. I loathe it. If I wanted to lead idiots around inside an area they might be having fun in, I'd have kids and take them to the playground. Worse still, is that in HL2EP1 (for which I will call this absurdly titled game from here on out) in the beginning, the idiot you're escorting, is actually more useful than you are. Sigh.
But I kept playing, I actually enjoyed myself from time to time when the game decided to make me feel useful.
The source engine is absolutely gorgeous and by now valve has had enough time to iron most of the problems out, though it wouldn't be a valve game if it didn't crash randomly.
It is a half life game still as well, so the most modest of poor decisions will almost always kill you, (more often than the combat) and poor performance in platforming segments is a sure fire trip to the quick load screen.
And after the 6 hours or so it'll take you to quick save your way to the finish line you'll end up running through hoops for an hour just so you can get the requisite 25 rockets it takes to kill what is basically just a cyberdemon on clown stilts.
But the game is still compelling enough to make you finish, which says a lot.
Is it as good as half life 2 even if half life 2 was split into small chunks? No, not even close. The worst of the original half life 2 is better than the best of episode one.