Contemplated not going with the Annex right away, but after the first camping trip I am so glad i decided to add it. Not only does it give some added privacy when climbing in and out of the tent, but it also provides a covered space for things like chairs, tables, stoves, shoes, bikes, etc. when sleeping. It rained the several times during my first few camping days and the Annex provided a great place to stay dry and comfortable without crawling into the tent. My son and i set up our chairs in the annex, had a drink and watched some videos before heading up for sleep in the X-Cover. It's pricey, but worked perfectly. The installation instructions should be updated for the X-Cover, however. The panel that sits against the vehicle connects differently than on other RTT models.