I am sure there are many good and many bad reviews on many different items. The main reason is because there are people who take care and properly clean and carefully store the probes and the unit, while others may just throw them in the drawer. Your tools must be properly cared for and taken care of. I am sure there are also other people who expect to receive high end laboratory grade equipment for $60.00...
When I first started out I had a Maverick and used it for two years without any issues. Keep away from water, carefully clean, and safely store and you will have no problems. I have since passed my maverick to another family member who started smoking and it still works today.
I never ran the cable through the vent, because it is he hottest part of the WSM/Kettle. The vent is where the exhaust, smoke, and heat exit, thus heat rises and it is always hotter in the dome than at grate level. I do not know what the probes are rated at now, but mine were rated at 400°, although the vent may not have reached 400° but I felt the extended exposure to high temperature can slowly degrade the cable insulation. I always notched or used a grommet in my cookers at grate level when I used the Maverick.
Look at the reviews realistically and consider the actual complaint, some will be valid, some are just idiots sounding off.
Bottom line is: for the price, it is a good unit and will give you many years of service if you use care when using and storing it.
Humphrey's Down East Beast, Weber Kettle, Kenmore Elite Gasser, Camp Chef Smoker, Camp Chef Denali