Best advice is find one that fits you and not someone else's opinion. Everyone is different.
You can usually spot a good used rifle on the shelf. Its the one that has been taken care of. You may find the usual handling marks, dings in the stock etc. but the bore and metal are clean.
But be forwarned. These may be on the rack because they couldn't shoot well and you may have to invest in some gunsmith work like trigger job, bedding etc.