Slot, tray, or top load?

None of the above. As someone whose CD transport is aged and limping along but also as someone who has recently entered the wonderful world of streaming I’d never buy another dedicated CD transport/player, and my next move is to buy something like one of the Innuos Zen streamers. They have onboard CD drives and internal storage to make it a breeze to rip all my CDs and can stream from my Qobuz service so I have access to all my music in any way/order I want to play it along with thousands of titles I don’t own. After experiencing streaming, being limited to playing individual CDs seems fairly absurd — kind of like having to reach into my pocket for change to throw into a toll basket. Ain’t no going back for me. Sorry I didn’t answer your question directly, but FWIW.

I brought up streaming as someone who was reluctant but who recently adopted streaming in the event the OP hadn’t thought much about it or what it might add to his/her listening enjoyment and how easy and painless it can be.  The OP can just disregard if they have no interest in streaming, but I don’t think bringing up other potential options an OP may not have considered is inappropriate in the least and can frequently be helpful and informative.  I know people have brought up solutions I hadn’t thought about in some of my posts and I greatly appreciated the information. 

That said, I’ve had three CD players/transports and all had front-loading drawer mechanisms.  Two of the three developed drawer problems so you can put me in the top-loading camp as well.  But even given my past experience, sound quality/characteristics would still be by far my overriding #1 priority.