OK, the reviewer is right about the brake switch spring, it is a weak point in the design. But the valve lash requires INSPECTION, not necessarily adjustment at the mileage he stated. This inspection and adjustment (if needed) are easy to do for most people who know their left from their right. If you are going to take your bike to the shop for every little thing, then expect to pay the price. This is true of anything, not just this motorcycle.
All valve adjustments say, "inspect".
Every bike I've ever owned has you "inspecting" the valve clearance at the regular service intervals. Inspecting and setting valve clearance is basically the same amount of work for either.
And it's not fair either to say that setting valves are a "little thing". Some bikes have very easy to set valves. Some, it's a nightmare requiring half of the bike to be taken off of the frame, special tools, and the like.
Regardless, valves should not have to be inspected at 1,000 miles.
I wonder is there is a connection between your low mileage (50 mpg) and your brake pad problem. This bike should get 70-75 mpg. Look it up. If the front brake caliper is sticking, it could cause the pad to wear prematurely. I would expect factory pads to last way over 1000 miles. I had a pair of EBC pads last only 3000 miles, and that was way too short if you ask me. I changed brands to DP Brakes sintered pads, and after 3000 miles that have little wear on them. The complete pad measures .264 - backing plate .120 means the original pad material is .144. After 3000 miles the pad material is .136. Measurements are in inches done with a caliper tool.
Also brake noise seems common. I occasionally run a hose over the brakes (while cool) and that seems to quiet them for me. Check gz250bike for lots of info (with no ads) on this motorcycle.