Your opinion on this installation PLEASE!

It seems to be normal with it very commanly also used for hot water services also. I dont like it like as movement will cause strain on the plumbing, however since they are not concreters the only thing that they could have used normally are galvernised brackets. In this example though it not your normal narrow condensor so it wouldnt have been solid on brackets as it comes to far out from the wall.

In hindsight you should have organised a small concrete slab. I made mine using a wheel barrow a bag of cement, some crush rock and sand and a shovel.

I thought ours could have been better but at least it's virtually flat on one concrete slab. It's actually sitting on some rubber feet on the concrete, for the vibration I suppose? We had ours done through a separate contractor too, and in retrospect it might have been useful to talk to each party about what was best to do as that side of the house is on quite a slope. We assumed since we were paying for their expertise they would, you know, do what they needed to do. The only thing was that because of the slope hubby came out one weekend and levelled the area where the compressor would go. Nothing special, just some flattening to save them some digging. So like I said, the unit is sitting pretty flat on a concrete slab (provided by them as far as I know) which is on a small area of levelled ground.
It doesn't look like you really have a slope, just a rather uneven pile of sand? I wonder if there was some confusion over who was responsible for doing a suitable base for the compressor? Seems to me they should have sorted things out, not just gone ahead and installed the unit like... THAT! I mean they couldn't even flatten the sand and stomp it down?
If this is typical of installations these days maybe it's because people are being led to believe it's the way it's done. If it's up to the homeowner to provide anything beyond some pavers and a rough pile of sand then they should be informed of that in a timely manner so they can make arrangements. But I think it's just sloppy work.

Thanks everyone. . . the contractor actually said "it's ok, the slab is included" when we asked about it, as we were going to have the builder create one for us at a paltry $132.

He's coming out on Thursday to fix up our zones and 'hopefully' relocate the return air, so we'll get onto him about this then. I just can't see that this sand won't just gradually wash away with heavy rain and leave the unit just hanging there. Phil was able to rock the unit back and forth by just pushing it. What is the world coming to where we're expected to put up with this kind of ** workmanship?

Get the installers back... The slabs should be flat on flat ground that is reasonably expected to stay that way... You don't want that donk fixed to the wall, trust me...!

What's happened here in the end?
It's just "amazing" what many "professionals" out there would be happy and proud to do. Just highlights how limited in thought is one of the pittiful "excuses" for substandard work by project builders - that some of their subcontractors do poor work only because they are paid peanuts by the builders - ??!??! I don't believe that at all. So, most of the underpaid workforce is doing a *** job only because they think they are poorly paid? "Nothing" to do with skill, knowledge, attitude and personal attributes ...

Hello everyone! Well, we would have had a slab poured, and the builder was going to do that for us, but the aircon installers told us they had it covered.

We had them back in and ripped them a new one. . . they said they were "always going to come back and finish off the job". . .yeah right! They finally brought some cement and concreted around the edge to keep the sand in place. It's not pretty but as least now the unit won't slide down the hill.