Hey all I have purchased 3-4 Ikea Kids Mattresses over last 3 years so thought I would post my experience. We brought the junior size 160cm however they use same design and model names for both COT and Extendable (full size) children's mattresses
Please note that while Ikea offer 25 year guarantee on Adult mattresses it offers No GURANTEE for Ikea Childrens Mattress (so if you have defector problem it is your problem and you will need to buy a new mattress)
Here are my thoughts on the 3 children's mattresses we have purchased in last 5 years (review date Jan 2018):
(i) Vyssa Skont / Sloa foam mattress (9cm thick), this is mid range Ikea mattress and has cold foam design with washable covers. The mattress is both comfortable and durable (we have owned this for over 5 years with multiple kids sleeping on). If you want a spring design for air movement you should look at VYSSA Vinka spring model but if you just want a simple comfortable supportive mattress for your kids then I recommend the cold foam mattress over the more expensive Ikea children's mattress (it has no moving parts so nothing to break)
(ii) VYSSA VINKA Bonnell Spring Mattress (12 cm thick), this is the cheaper of the two Ikea spring mattresses but is slightly thicker than the top of the line pocket mattress (the Vackett). We have owned the Vinka for 2+ years with no major problems. The springs and padding are reasonably comfortable (though not as comfortable as Ikea's foam mattress) and mattress seems reasonably durable (TBC if bonnell spring will suffer same issue as Vackert pocket spring mattress over next few years - see below)
(iii) VYSSA VACKERT Pocket Spring Mattress (10 cm thick): AVOID - we brought our VACKERT mattress in 2014 and it developed gaps in padding / holes in springs (within 2-3 years of purchase) - see photos. The pocket springs separated from foam cover due to poor design and bunched up leaving gaps / holes in mattress support. Ikea refused to replace or exchange the defective mattress after 3 years (they said there is no guarantee for children's mattress) so I do not recommend this model as most expensive and worst quality (see my separate VACKERT review for full details). Interesting we had the same pocket spring problem with one of our Ikea Adult mattress but as this adult mattress was covered by Ikea standard 25 year guarantee, Ikea immediately replaced when we raised problem and we still use the adult mattress
Hope this review helps and if you are buying a children's mattress and Ikea staff do say they offer a guarantee please get response in writing and post a photo