I have been working at Index Exchange full-time
This company really puts great emphasis on then Engineering teams. They work hard to make sure we are all satisfied.
I can't really think of any cons.
I applied online. The process took 3 weeks. I interviewed at Index Exchange (Waterloo, ON) in December-2016.
Nothing really different from what everyone else has said. Coding challenge on Codility was first -- as someone else mentioned, you have to go about the string manipulation question the correct way first, otherwise you won't have time to finish comfortably. The SQL part is challenging enough if you have not had experience with non-trivial queries. I didn't do extremely well on this part unfortunately.
I was told within the next day I'd have a phone interview, they gave me the topics beforehand too. The interview itself is a lot of definitions, but if you don't really know this stuff, some of the questions could throw you off. I thought it was pretty painless. Interviewer was very pleasant.
Since it was snowing pretty hard I was offered a Skype interview with a lead engineer for a technical interview a few days later. Two SQL questions, they expect you to walk through your thoughts with them. Then I was assigned to create a data type in an object-oriented language; here they want efficient solutions, and they want to know why. Very friendly interviewer, but she will challenge you on your solution. Some behavioural questions too; Index wants people that are fun to work with. Even if you're a good engineer, you may not be a good cultural fit for them.
The next morning I was told I was invited to visit the Kitchener office to meet the Engineering Manager and a lead engineer for another chat. This wasn't very technical at all; some questions about my experience in my former positions and as a developer in general, but mainly just personal questions. Again, here they really wanted to get a sense of me as an individual. However, I'm pretty sure I was the only applicant with an interview that day, so I think it was mostly a formality. I received an offer a few hours after I left.
All in all, the process was not stressful, and if you're prepared and well-versed in the topics, you can do fine. Everyone is very friendly and want to make sure you succeed, but they have their standards too.
I didn't negotiate, I'm still fairly junior and what they offered was what I expected.