If I am not mistaken,
Previous case,someone exchanged (or got repaired),tested on the spot no problem,
went home and problem occured 

yup... perfect HTC one here..

eventhough the specs is not as good as others... the smoothness... is miles ahead than others especially samsung

My bad experience with the htc service so far
Conclusion , from the beginning (courier picking ) until now (claimed that my phone is doen with the repair , prepare to send back )- even my phone is come back with perfect condition (which i shouldn't expect so =.= ) , i won't change my rate regarding service quality , attitude and behaviour of htc .
1. on 12/8/13 , called the customer care to assign courier to come and collect my phone , according to them , the courier is able to come to my doorstep to collect my phone. they claimed that 2 days later , the courier should come.

2. after a long wait , on 19/8/13 , the courier contacted me and he said he won't be able to come to my place , he asked me to go to the town and meet him up ! (my place is merely around 15 min from the town ! ). Fine , i told him to be punctual and come at 12pm , he said he is at home and only able to come out at 1pm ! I told him to be punctual because i got work to do , i need to go back to office on time and he was late for 30 min !

3. i was expecting some formal procedure and paperwork should be done upon collection(to prove the phone is collected by courier and my phone was functioning ). The courier only prepare 1 plastic bag to carry my phone. according to the courier , there is no such procedure or paperwork from htc  to guarantee the safety of my phone . This is scary !

4. according to the courier , my phone should be send to kl after 2 days , and according to the customer care line A , my phone has reached the service centre at thursday , and they started to accessing my phone.

5. On 29/8/13 , i called the customer care line , according to customer care line B , my phone just arrived yesterday and now waiting for assessment . then i said wth ? my phone just arrived yesterday ? it should be arrived last thursday ! the customer care line only able to quote the " according to the system data , your phone really arrived yesterday . "

6. on 2/9/13 , according to the htc customer care line C (another guy ), he said the repairing work is done , should be able to finish next week . When i asked what is the diagnosis made by the technician , he said no data or feedback sent from the service center.

7. On 9/9/13 , i called the htc customer care line again , the customer care line B back in action , she said according to the system , my phone still under assessment . Then i was very pissed off and asked , what kind of service is this ? using time machine to change my phone from under repair to under assessment ? Me : is that really difficult to get the info from the service center ? Care Line : We only take the feedback from the customer and the feedback will be sent to customer service center via my supervisor . There is no phone number for the service center at the berjaya time sq and kelana jaya. We communicate with them using email ? Me : oh , such a great system , so basically service center and customer care line are 2 different body which work in isolated manner ? Customer care : yes Me : so basically whatever bullsh!t done by the service center , u all have to get scolded all the time Customer Care : Yes Me : fine . i got nothing to say .

8. after the long wait , finally got the call from htc , customer care : Hi mr ng , We are here to tell you your htc sensation is done with the repair me : what the fxxk ? go home you are drunk ! i sent my htc one to repair , how come become htc sensation ? Customer care : we will check again After that , i called the customer careline again . My device is htc one. I complaint about the lousy service from the beginning and from the core. I warned them that i will ledge a police report if my phone bumper case (i sent the phone with case attached due to safety ) or the phone turns out to be htc sensation . the customer said i can do whatever i want . the attitude really horrible , they made so much joke for the service , how i supposed to not to worry about my phone !

Conclusion : HTC makes good phone , but the customer service assigned by HTC (mine one is SIS Malaysia distributor ) is really horrible .. piece of shit !! it takes me around 6 weeks to survive without my phone. My phone went through some magical process (time travel and magic )
Advice : Customer service quality should be considered when u purchasing phone. Sub-standard after sales service can turn u upside down . be careful .

My phone came back with acceptable condition ...  but once the temperature shoot up to 40-43c , the purple tint issue reappear again, even the phone is just repaired , after 6 weeks stay in KL. I bet there is a design defect in the camera and also the phone structure. the heat badly affected the camera performance. think twice when buying htc product. i plan to let my htc one retire next year, if budget is allowing me to do so. Samsung scored 100% with difficulty of 4 but htc one scored 50% with difficulty of 10 .. what is ur opinion  ?

False, Its a hardware issue, can occur whenever. One trigger seems to be heat.
Must find the chance to try that.