I received many invites from One Plus team for One Plus X, but initially I ignored the invites but later I bought this phone for my wife. My wife wanted a stylish phone with decent performance. So, I bought this phone and used to for almost 2 weeks before handing it over to her(still I use it every day for few hours or minutes).
To tell you my experience in pros and cons:
Pros:
Style: This phone is made up of glass hence it looks very premium in hand. Since the back panel is made of glass it catches fingerprints very easily but that can be ignored. Many people do ask about the phone.
3GB RAM makes multitasking and gaming very easy. Sometimes my wife forgets to kill apps running in back ground for 2 to 3 days. Even though the performance of the phone does not decrease at all. It does multitasking very smoothly.
AMOLED screen. The display is very very sharp. The colors re production is so good. even sun light visibility is very good on this phone. it has gorilla glass protection as well. Now a days all phones comes with gorilla glass protection.
Sound out put: sound quality is decent and not that bad. Sometimes I feed it is little bit low but in day to day uses one can manage with this much sound out put.
Cons:
It has those hybrid SIM slot. One can either use one SIM card plus one memory card or Two SIM cards and to add to this it has only 16 GB of internal storage. One plus should have given at least 32 GB since it has hybrid SIM slot. This is a major con for me as we use 2 SIM cards; one for internet and one for calling. 16 GB is enough but at times we require more space.
Battery life: Battery life is average. It has 2525 mah battery and with AMOLED screen it runs out fast. with low to moderate use, it gives screen on time of 3 hours. To be very frank this is not the phone you carry while travelling or you require a power bank always with you. Carrying a power bank becomes a headache some time.
Now, if your usage is low to moderate and you are not using 2 SIM cards and this is the best phone you can buy. One plus is new brand but trust me they sell good quality products.