Heavy duty amp stand, Sonic benefits?

As always it is system dependent. I went to look at your system and noticed it gone.

I have used amp stands for decades. I have high quality amps, tubed now. Originally I remember a small improvement. It is likely adding 100 lbs of amp stand will help, just from the mass.
 

I recently put springs under mine (on the amp stand under the amp) and definitely noticed an improvement.

I have been toying with this idea while talking with an Audiogon member that whether cones (spike like) or springs are more effective might be that coupling with a suspended floor (which may already have absorbed micro vibrations) is better and springs are better when on a cement ground floor (since direct coupling with the ground will pick up micro vibrations) work better. He found cones worked better on his suspended floor and springs worked better for me on my concrete ground floor.

I’m planning on buying a seismometer in the next year or so, so perhaps I would be able to experimentally substantiate (a little bit) the idea.

Anyway, the amp stand with spikes or cones under on a suspended floor might be the best. And the amp stand with springs or anti vibration devices on concrete might be the ticket.

I made my amp stands out of 4" thick solid maple. I then installed 2" Audio points underneath and Herbies sliders under the points. Under the amps themselves I have Critical Mass footers.

ozzy

Is there any problem if I use casters on my amp stands? I never understood how people move their amplifiers without casters. 

Most people probably don't move them very often.

Not sure if casters are a great idea under the amp stand and may nullify the benefits by reducing stability

I use SolidSteel S3-A amp stand and it’s pretty good. Did I notice any improvement in sound? Not sure. Never A/B’d before and after.
They look nice though and not very expensive.