Personally I had no real issues with installing the metal spike in the soil. It's long, which means plenty of hammering and trying to keep it straight as it goes in, but with a bit of care it's pretty much perfectly straight and certainly very secure in the ground.
Got the 40m stainless steel version. Absolutely excellent apart from the overly loose plastic spike which I set in concrete. Used a level and packed it in to get a true upright. Still a bit wobbly. The soil spikeis wose according to reviews being about 54-55mm wide. So if you can cope with an off centre airer this is truely excellent otherwise. https://www.amazon.co.uk/gp/customer-reviews/R2S6G24SRHD5QH/ref=cm_cr_getr_d_rvw_ttl?ie=UTF8&ASIN=B008AUY602
Got this for £45 on Prime Day last year........The wife is still getting on at me about I have still not 'installed' it. She only mentioned it last week also. In my defence I went to do it once and the holder was bigger than the one we have now so it required a bit of work so I said I would have to look at it when I had more time....
Haha...Cheers Candystore. I'll put caps lock on to get the full effect!