I have the Yellow etrex (Etrex venture HC ) , and it locks on fast its about a $100 item - sorry not the particular item you are looking for
uses 2 AA batteries and navigates plenty good for me - I remember one time I was on a plane and one of the passengers wanted to know how long we had till landing , I tuned it on pressed it against the window and in less than a minute I told her we were flying at 480 MPR and we just passed over the Kansas border - its amazingly compact and easy to use - I can find trails down to the yard in pitch black with my etrex
If I tun it on it takes on average about 1-2 minutes to lock on , Ill turn it off to conserve the battery , and when I turn in back on , it locks on real fast less than a minute - its a good little unit