Migrating from IPB3

[Cafey]

Currently I use vBulletin4 my forum, but over the development appeared many bugs and very slow, which left me completely disappointed.

I'm thinking of replacing it by IPB3, but I still have doubts about plugins, styles and optimization.

I help to employees, if it is worth migrating to IPB3 or would be better to keep the version 2.3. Although the use Vbulletin for 4 years, I realized that their system no longer meets my needs.

Now I need a forum fast, clean code, no useless features, taking into account a great demand of users.

I have an average of 50,000 visitors per day and average of 3200 users with a fast-growing daily, 890,000 posts and 750,000 registered users.

In both versions which would be most appropriate?