Don't use one. Object Dock worked for a couple years but lately I've been using Object Bar.
With OB2 I normally have my task list in a bar at the bottom of the screen but usually have my Start Menu at the top. With OD+ I like to have running task list along the right side with everything else on top.

Haven't used the Windows taskbar since 1999.
My "Running Tasks" dock is on the left side of monitor #2....
My "Systray" dock is on the left side of monitor #1...

how does it compare with object bar 1 or object dock in memory usage? (not Mem usage, but VM size)

I don't have OB1 installed so I can't comment there but as for Object Dock Plus 1.5...........
It looks to me like Object bar uses less physical resources....but judge for yourself.

It depends on the setup at the time. There's been only a few times I've auto hidden it. The Taskbar is an important part of the skin, I try to blend it in with the wall. It's all part of the vision of the artist who made the skin you see. I try not to use quick launch. I'd rather use Object Dock, it's such a cool program. I like Tabbed Docks the best. I'd say That 90% of the time my Taskbar is on the bottom.

so i was wondering if there is a way to make it behave in a way similar to tabbed docks?

Yes & no...... it can be set up to display icons only for shortcuts which would be comparable with OD but it also can have custom menus, embedded widgets, folders as menus etc. but it cannot cycle thru different bars comparable with tabs. It's more like the Windows Taskbar on steriods. For instance my task list is graphical, I've got it setup to only show icons and not text. I also have several pop menus that have a top level icon only and no text.

OD Plus is much more Eye candy than OB2 but (once we get some more documentation) I believe theres a lot more OB2 can do overall. One thing that may interest some people is the fact that I would always have to exit OD+ to play a game......I don't have to do that with OB2.