The first half of the show (up through episode 12) was simply wonderful, hovering between 8/10 and 9/10 for me. I don't even mind what happened on episode 12 — I thought they were both right and both acted right.
But.
Between episode 13 and the end, it kept drawing out, and out... and out. It became a true shoujo soap drama where one character picks on the tiniest little things and makes the relationship unnecessarily difficult, while the other character can't get away from the past. It was slow and tiresome. I just didn't enjoy this second half very much, but it was still watchable, and you will probably be able to stick through it. Unfortunately, the ending is nothing really worth waiting for anyway.
The main girl, Nanami, plays it so perfectly in the first half though. The way she talks... if I hadn't seen the second half, she'd easily be one of my favorite characters. Animation: low-budget mediocrity galore with mostly static frames, but they do try to be artistic with it (e.g. all the bubbly framing around key scenes, or how they occasionally blank out one eye for effect). Pacing: slower than average. Music: gently compliments every mood, insert songs never feel unwanted or out of place, and they cycle through a remarkable number of ending themes (9!).
All in all, I definitely recommend at least starting Bokura ga Ita, and if the front half leaves enough of an impact, perhaps try a bit of the back half for yourself. It's certainly not awful, but just nowhere near as alluring as the front's wonderfully carefree slice of life, and far more irritating. And it may leave a bad aftertaste.
P.S. — If you do watch the entire thing, be sure to check the manga for the last episode since they leave out a key line after the anime's final scene. (It's in the last few pages of Chapter 31. You'll know it when you see it, but feel free to ask me if you're uncertain.) And if you're up for it, there are 39 more chapters to Bokura ga Ita after this.
