I use strictly Exped mattresses with Helinox cots. Very high comfort and durability. However, they're very expensive, and in the last couple of years a number of new companies have come out with similar mattresses that cost a fraction of the Exped/Thermarest/Nemo/etc. prices. I've been watching the OTGR (The Outdoor Gear Review) channel on YouTube, which has reviewed some of these new mattresses, along with cots that are similar in quality to the $450 Helinox cots.
When I first started buying mattresses and cots 10 years ago the choice was limited to low quality/low price and high quality/high price. If I had to start over, I would give these new high quality/low price brands a try.
I would say the same about tents. More recent brands like Naturhike are making high-quality tents that cost $130, not $450 like Nemo, MSR, etc. Ditto for down sleeping bags, stoves, fire pits, chairs, tables, and so on. I have hundreds of dollars invested in a Helinox cot, chair, and table. Today I could get the same quality for 1/3 the cost of Helinox.