Depends on your goals. If you go with WordPress + Invision Community you essentially set up two different websites — one for the blog, one for the community. If that’s fine with you, you can do that. If you want your blog posts to be PART of the community, you should go with Pages.
Others have correctly pointed out that Pages has a steep learning curve in contrast to the other IC apps and WordPress, but learning how to do it might be a small price to pay if you run the website for years to come.