Jessem Excel router tbl ?

I'm currently considering a Jessem Excel router table and I was hoping someone might be able to answer a few questions about their performance and operation. My first concern is having the raising gear box placed in a location that looks prone to bumping. How easily would bumps cause the hieght to be altered, or is their a lock. Second question, does the gear mechanism work well or is it sloppy and prone to slippage. Third question, how is the phenolic top. Any help would greatly be appreciated. Bob