This hike was amazing. Mountains, lakes, waterfalls, mountain meadows, wildflowers, wildlife. You name it, it is all here. If I could have given more than 5 stars, I would have. The walk in was one beautiful view after another. Take the time to take the Lake Ann side trip at about 1.3 mile in, but bring a LOT of mosquito repellant. It is pretty, but you will get eaten alive. Actually, you hit the mosquitos before the lake, so apply that repellant before you start the hike. Leave the lake and the climbing really starts, but it is actually fun because you will have to keep stopping to admire the scenery. Listen for the marmots (HUGE marmots, at that) whistling to each other that you are coming.
When you get to Heather Pass (before Maple Pass), take the time to veer off on the trail to the right and hang out up there for a while. The views to the northwest are gorgeous. Keep on to Maple Pass and head past it a few hundred feet for the best views to the west and southwest. The glaciers are awesome.
After Maple Pass, you have to climb more, but then you start descending through some fantastic meadows and along a ridge that drops away on either side to Lake Ann on the left and, eventually, Rainy Lake and it's waterfall to the right. Watch your step through these parts. The ground tended to be loose and we slid a few times.
On the down side, the last 1/3 of the hike was nothing worth writing about. It was just endless descending switchbacks. It was almost as if they gave up after that point and just hacked a path with no planning. You end up on the paved path back to the trailhead.
My wife and I did this one together, and we thought it was a little harder than it was rated. We were really tired at the end, but we are not hard core hikers, so others might think it easier than we did. We would do it again today, if we could, but this time we would go up to Maple Pass and come back the same way.