I don't really bother with sportives, I don't find them all that enjoyable and also feel the VFM is generally very poor! I would rather enter a 100 mile TT or something like that where I am challenging myself and actually get a result that counts for something at the end.
I can see why some people like them though, up to them what they spend their money on and if they enjoy it, great! I pay £20 a year for club membership and ride in a group 2-4 times a week for between 40-80 mile at a time, so a sportive to me is generally the same thing, but with other people getting in the way (especially on the hills when people start slowing to a crawl, weaving all over, falling off and dismounting and walking around in the road instead of getting the fark out of the way) and my wallet £20-25 lighter.
I am also not a fan of Audax, for different reasons, I did one recently, enjoyed the day out with my club mates, the banter etc and the organisation and VFM were good, but it is just not for me, too much time sat in the saddle just paddling on at a steady pace.