I'm going to say 60% disappoint and rarely meet expectation (forum or developer generated), 20% I feel ripped off with (post release shenanigans), 15% are so-so and about 5% actually offer something fitting for the device and are enjoyable. Also for the OP, the simulation genre you like has unfortunately been gutted on iOS as it's pretty much bread and butter Freemium on the platform (and Facebook).
Thanks to a few developers stiffing supporters with post release ads, switching to a freemium model or locking customers out of content they paid for, I haven't bought an iOS title for close to 6 months. And I was a pretty avid spender. Can't be bothered with the lack of integrity or accountability.