The small ones don't have enough columns to keep track of all the categories a pro-pilot might need. My suggestion would be to keep the small one until all of your instructor ratings are done, then get a big one. That way all of your endorsements and checkrides are in one logbook that you can put in a fire-proof safe.
Or double-bag them and put them in your freezer...the freezer is insulated enough to survive house fires in many cases.
Future airline employers are VERY sceptical of missing logbooks,even if you have copies. Some require original, hard-copy logbooks.