This is my experience with Oneplus service centre in Coimbatore (SriVari Computers, Gandhipuram). My wife's OPO screen broke after a fall, and had to be replaced. Using an OTG cable with USB mouse, I confirmed that everything was working in order, and only the display + touch assembly had conked off. Initially I had considered replacing the assembly myself, but decided against it.
My nearest OPO service centre is in Coimbatore, 100+ kms away. There were two centres, and after calling both, I came to know that I need to send an email with a copy of invoice to them, so that they can procure the replacement part. The guy in Srivari Computers was much more responsive to enquiries, and he assured me that he can replace the assembly in less than 2 hrs and give it to me, so I needn't make two separate trips. I mailed them the details on a Tuesday, and on Thursday I got a call saying my replacement part had arrived, and I could get my mobile serviced any time. Went there on Friday, and it was replaced perfectly within an hour.
Replacement cost me about Rs.8000. Thankfully, Oneplus has put up a price list for spares along with labor charges on their website, so the bill was not a surprise. All in all, a very pleasant and hassle free experience.
TL;DR version:
Had to replace OPO broken screen >> mailed the bill to their service centre >> spare procured in a day >> was replaced efficiently. Pricing is transparent.
Link to their pricing details -
https://blog.oneplus.net/india/2016/01/04/customer_support_update_5/
https://s3.amazonaws.com/oneplussupport/OnePlus-Spare-Part-OOW-Price-India.pdf
My nearest OPO service centre is in Coimbatore, 100+ kms away. There were two centres, and after calling both, I came to know that I need to send an email with a copy of invoice to them, so that they can procure the replacement part. The guy in Srivari Computers was much more responsive to enquiries, and he assured me that he can replace the assembly in less than 2 hrs and give it to me, so I needn't make two separate trips. I mailed them the details on a Tuesday, and on Thursday I got a call saying my replacement part had arrived, and I could get my mobile serviced any time. Went there on Friday, and it was replaced perfectly within an hour.

Replacement cost me about Rs.8000. Thankfully, Oneplus has put up a price list for spares along with labor charges on their website, so the bill was not a surprise. All in all, a very pleasant and hassle free experience.
TL;DR version:
Had to replace OPO broken screen >> mailed the bill to their service centre >> spare procured in a day >> was replaced efficiently. Pricing is transparent.

Link to their pricing details -
https://blog.oneplus.net/india/2016/01/04/customer_support_update_5/
https://s3.amazonaws.com/oneplussupport/OnePlus-Spare-Part-OOW-Price-India.pdf