The >300lbs on a GeekDesk Max isn't how much it can support, it's how much it can lift. Your office chair can't lift 300lbs. It can't lift much at all. I also don't believe in the ability of a pair of $300 hydraulic lifts to consistently reproduce my presets.
As someone who weighs close to 300lbs, I can also tell you you won't find a good office chair rated for 300lbs for under $100. Go look at the specs on office chairs closely. Most of them will be rated for less than 250lbs with no more than a few hours/day of use.
If you want your own crappy top (planks? really?), the actual cost of a GeekDesk Max is $725-745. The non-max (275lbs lifting capacity) is $525-549. You want a vastly inferior product to save $225?
I got a geek desk, the original. Put my own top of plywood on it finished. I've got 3 24" flatscreens and abunch of other crap. I'm still not even near the lifting capacity. But I think of the higher end desk as a good idea for a quieter motor, not so much the need for more weight. With that said, I think a hand crank desk should be fine for most of us. If only I could find one that's reasonably cheaper. The hand crank desks I've seen basically cost the same as the geekdesk though, which I don't understand at all.
50lbs desk surface, 3x ~15lbs LCDs, 5.6lbs laptop, ~15lbs desktop, other electronics, lamps, some books, papers, stands, containers with misc parts and things, whatever else I might be working on.
It's a 6.5' x 2.6' foot surface, it holds a lot more than a laptop.
As someone who weighs close to 300lbs, I can also tell you you won't find a good office chair rated for 300lbs for under $100. Go look at the specs on office chairs closely. Most of them will be rated for less than 250lbs with no more than a few hours/day of use.
If you want your own crappy top (planks? really?), the actual cost of a GeekDesk Max is $725-745. The non-max (275lbs lifting capacity) is $525-549. You want a vastly inferior product to save $225?