TinkerCad vs 3dTin vs Gogle SketchUp

TinkerCad vs 3dTin vs Google SketchUp from a 3d printing perspective

Though I have used TinkerCad the most among the 3 & perhaps havnt used the other 2 enough to truly know their capabilities, Ill share an opinion as more of a beginner.

Summary:

If you want really easy & are new to modelling, TinkerCad has hit the nail on the head with being the simplest product of them all.
Straight forward & intuitive, you know what you are doing. A newbie will love the convenience & natural approach of the UI. The models genuinely are easy to print with fdm 3d printers.

If you want ease, but acept that TinkerCADs lack of any real toolset except for the 1 hole utility is starting to hold you down, then 3d Tin is definitely a good balance.
The problem with 3d tin is that it creates very poor textures, especially when you use a curved surface on a custom created shape.

Google sketchup is very useful if you want to use dimensions & create a very geometric item.
It allows you to make additions by drawing faces, which is quite useful when you want to create little cahnnels on extrusions in an already created object.
Its not fundamentally designed to create water tight models automatically so expect lots of open faces & unclosed walls, or holes, which you might need to check with netfab.

Im not going to hold that against sketchup though, because every modelling tool is designed with a certain approach, 3d printing just isnt SketchUp's approach. They work at the 'face level' on the mesh, & that is a fundamentally different way of modelling than the other 2 compared here.
It doesnt work too well with FDM 3d printers if there are any unclosed edges, but if you follow good model creation discipline, sketchup is ok.
But I did find sketchup to be quite frustrating at times, & also quite slow for complex designs.