Buy what you like. It likely won’t help with work, but at least you will like it.

rjohnson11
Go with your gut. If you want it then buy it. 

This...if it's ergonomic for you ...if you like it....then by all means....buy it.

ForSerious
Actually these are some of the better mice to buy for work because they store profiles on the mouse itself. I've had ultra-locked-down computers for work before, and I could still have my copy/pasta buttons on these mice.

Came here to say this. With our KB/Mice you can create macros/key assignments on your home system, save the changes to your profiles, then use the same bindings/macros on your work system without the Unleash software installed. 

zomgtruth
.. it stops functioning after about 4 months, then all you can do is look at it. Seriously do your research before pulling the trigger.

False. False. True.
Add this to your research: I have had and used my X17 for a year and seven months. It gets used 8+ hours most days for work and play. It still has about a year and a half on its warranty. If it broke tomorrow, I could get it replaced. Sure some products have defects, that's just reality and why they have warranties on things like this.
 
If you look at forums like this or reviews on shopping sites, keep in mind that unless people are getting incentivized to leave feedback, ~20% with a good experience will leave feedback while ~80% with a bad experience will.

HeavyHemi
I'm on my FOURTH Corsair M65 RBG pro on the third RMA. Left mouse button every time and I'm easy on mice.

What are you saying? Buyer's remorse… EVGA is not Corsair… You did your research yet still picked a dud?

I think the term "expensive" probably makes this a more challenging thread than it needs to be.  I think the most important question is whether the mouse you're looking at has a positive effect towards your working environment.
 
If you need an ergonomic mouse for carpal-tunnel reasons, or if you need assignable buttons because you use a lot of macros, or you just need to find that one mouse that fits your hand well, there's tons of options out there.  Some people also have a very strong sensory reaction to the way a mouse might feel when clicking, using the scroll-wheel, etc., and this may also influence how you get through your workday.  I once used a gaming mouse at work that had a throttle button on the side that made scrolling through pages or documents so stupidly easy that it made life that much easier when it came to reviewing or reading certain types of content.  I saw an article recently where the author discussed his appreciation for a specific competitor's mouse because it greatly helped the author with a variety of Photoshop functions after spending some time customizing it.
 
The bottom line is that all of this stuff is really personal and needs to be evaluated based on your needs.  It's just like a lot of people bring their own keyboards to the office these days, if a certain mouse helps you improve your productivity or even just makes you feel better for looking at it and/or using it, then it doesn't matter if it's expensive or not.  Finding your perfect mouse isn't easy, so you just have to give one a try if you see one that piques your interest.