IHG works well if you like staying a lot in cheap properties of dubious quality. Most of the brands are incomparable to Starwood or Marriott which are higher quality chains across the board.
The lack of structured loyalty programme with clear benefits (including defined upgrade path and club), make IHG stays way too random for me. Even as a long term RA I am finding IC's are losing their lustre exacerbated by recent scheme changes.
IHG is great if you like to stay at cheap often low quality properties in a lot of locations, don't have much expectations of status and are content to rapidly earn room redemptions for basic rooms but with tight reward inventory capacity control (there is no equivalent "no blackout" policy to SPG).
To my mind IHG Rewards is not a good substitute for a proper hotel loyalty programme like HHonors, SPG or Marriott Rewards. That and the relatively lowered property portfolio really means that IHG properties tend to be my third choice globally except if there is an IC available.