Though being an EXASOL guy, I will not start to try to convince you that EXASOL is the one and only good solution out there. It heavily depends on the use case you are trying to implement, and the requirements you have to fulfill.
Hadoop is a very flexible, scalable system and used very often for storing and processing huge volumes of data.
EXASOL in contrast is a specialized RDBMS for complex analytic query processing.
I think that these two options don't really directly compete but complement each other. In many cases companies need a scalable data lake to store and preprocess there data, or to query it in rather simply ways. Once you want to enter the real-time business with complex analytics, where dozens, hundreds or even thousands of analysts are running lots of queries, then an in-memory RDBMS is a great choice.
King, the producer of Candy Crush, combines these two worlds to a powerful data management eco system. They store petabytes of data within Hadoop and use EXASOL on top as an in-memory layer for hundreds of terabytes of data. You can read more about that exciting use case here: http://bit.ly/1TR8APY
Another important difference of these two worlds is the complexity. While EXASOL is tuning-free because it is a specialized system (similar to an appliance) for a certain use case running SQL queries or R/Python/Java in-database-analytics, the Hadoop stack is much more complex. You'll need a certain level of know how to setup, maintain and tune this system. This doesn't need to be a reason for any of the two option. As mentioned, it heavily depends on what you want.
From a price perspective, Hadoop is free and so it should be much cheaper than an in-memory db such as EXASOL, right? Wait a minute, it's not that easy. Again, you have to consider the whole picture. How much data you really want to store, how much of that needs to be queried for analysis, how much hardware would you need to buy, how many people do you have to be hired and trained for the operation or the analytics deployed on the system.
Summary
To summarize my thoughts, the world is too complicated to directly compare these two technologies. Depending on the use case and your personal requirements, either one or the other could be the better option. And in my opinion, the trend in the market is combining such systems to a data mgmt eco systems where you get the best out of the two worlds... Actually three worlds, because the world of operational data processing of NoSQL solutions should also be mentioned here.
I hope that helped a bit. If you need any further details especially about EXASOL, don't hesitate to contact me or connect with me on LinkedIn: de.linkedin.com/in/exagolo