[bojan]

Yep – someone on this forum said the best telescope is the one that is used…

After power up OnSTEP starts assuming the scope is in home position (it was conceived for EQ mount first). However, you do not have to worry about that too much - I switch on my version of OnSTEP system connected to laptop running CdC, then I point the scope to bright object and sync - and that is giving me enough precision for GoTo and so I have a full control of my EQ6 from my laptop screen.
LX200 is supported on both serial ports, in my case USB is used by CdC for positioning, the other serial port on MEGA board I am using for guiding (normally it is used for wireless communication). ST4 port I use for fine manual control (buttons on housing).

The best thing about OnSTEP is that you can use this firmware (or, I should say "sketch" as I was warned by someone on Arduino discussion forum that I will not get very far with term "firmware" ?? No idea why is that ) on variety of platforms, some of them are really cheap ($5max on ebay)
Have a look at OnSTEP group .. you can ask questions there, Howard (and other contributors) is very helpful.
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I am also using Bartels system on my 10” Dobson.
It is sort of considered "obsolete" these days (because it runs on DOS platform), but many people still use it because of its flexibility and because it works. And it is still better (with more features) compared to any other freeware available.
I am running Bartels software on Fujitsu ST 1000 pen computer (100MHz 486, with CF card as HD - the whole thing cost me about $50).
Upon power up, I can either sync on SCP or on any other bright object, and encoders (taken from old mechanical serial mouse) take care of manual pointing (or I can GoTo if/when needed.

You can see some details here about my mechanical solution (it is not ideal either - I need to add rubber rollers on the rim to minimise vibrations).