Personally, the only things I need from a Pokémon site are an online 'dex, news, and random factoids that I might use in fanfiction. I tend to just glean news from forums and Bulbanews, it's easier to search for random facts via Bulbapedia's search engine, and Serebii's separate 'dexes combined with the inability to right click mean I have to load the site's front page and navigate from there multiple times to get all the information I need from an online 'dex. (I could just save everything to my bookmarks, but even then, I'd have to switch back and forth between tabs when I'd rather have everything about every generation on one page.) Not saying that the information is bad. I'm just saying that it's easier for me to go elsewhere. For example, I'm sure having separate gens in their own 'dexes works for some people, but it just doesn't for me for my own reasons.
In other words, I'm sure it's a great site, but it just doesn't fit my needs. So, I'm more indifferent to it.
The forums I haven't sampled enough, to be honest, so I can't comment on it, really.