Like PC World I only ever buy from CPW when the item is on offer and cheaper than anywhere else. But saying that our whole hose is now on Sim-free OnePlus phones and I think that this is the way we will go from now on. We stay a generation behind as it doesn't matter so much and good deals can be had - our 5Ts are almost brand new and my other half is amazed at the monthly updates considering her last Huawei had no updates in the whole time she owned it. If you can afford the up front cost then there is no reason to have a contract phone.
Also if you're in the UK and use BT for your phone and internet then there are some good deals to be had on sims through them (I know loads of you hate BT but they are the most reliable for me and working from home I need high uptime)
Biting the hand that feeds IT
