i think that pass is for loon, waterville, and cranmore, not cannon... unless i am mistaken. if it includes cannon, it's worth it hands down.
regarding loon, loon is a pretty solid mountain overall. they have some fun expert runs (but they are not too tough). their squares are great for straight a head cruisers. unfortunately, for both waterville and loon, being the biggest ski areas closest to the boston metro, they have HUGE crowds on the weekend. to the point that despite my liking the expert terrain area, i will only go mid-week.
also, stay away from the gondola when you go, that's the worst. it's a long lift that's fairly slow (for a high speed lift) and is always crowded. it's best to ski loon as right side/left side. use the high speed quad for the right side and the double and the triple to access the expert skiing and the rest of the upper mountain.
i'd recommend you visit loon on a weekend before investing in a pass.
currently, loon has about 50% open, only 1 diamond. most of their greens and blues are open. i got that info from their web page, i haven't visited them this year.