Do you think that this is a good device to use in a yard of engines?

Check ebay they might have some.

Currently I am looking to buy a Peco Loco Lift. Can anyone give me any comments or tips regarding this?

Very interesting that you say that about the weight problem because this was happening to me as well. I do not know were you have your switch on the layout or how much traffic that switch gets but what i did(keep in mind that my switch does not get a lot of traffic)is I use a skewer or a small needle nose plyer and physicaly hold the switch in place as my locomotive goes succesfully over the point. Hope this helps you! If you would like more you may follow me on twitter, my username is trainmanjay. 

Also most hobby shops will take a peek at your locos for you for free

Well unfortunately trains under the EZ command system seem to be very sensitive to things such as dust and particles on the track. What I would do is to regularly pull a cleaning car with most if not all of your consists.  If you still need help visit me on twitter my username is trainmanjay
Hope this helps you!