Sandisk vs Lexar? No problem with either one provide you avoid the very cheap, slow models.
Do the math/equation for the Gb and speed per $ sweet-spot. B&H recently had a great deal on a two-pack of 32Gb Lexar 1000x UMDA7 cards so I stocked up. These fast 1000x cards make a very real, tangible difference in my 5D3 & Mk4 with a deeper usable buffer and way faster clearing time compared to the previous Sandisk Extreme cards I was running with.
Like others, I have never had a CF card fail, corrupt or behave badly. In 12 years of CF card use I've has Sandisk, Trancend, Ridata and Lexar. A few of them have gone through the clothes washing machine when accidentally left in my jeans pockets and they just came out cleaner. No problems.
As a possibly over-the-top form of insurance, I don't use CF cards for more than a couple of years before updating to fresh cards.