Of Emma's two Deluxe hybrids, the Emma Helix Hybrid Deluxe Mattress is the one I'd buy. It leaves out memory foam and puts gel foam over zoned reflex foam and pocket springs, which makes it a springier, cooler medium for combination sleepers and anyone who runs warm. I'm still no fan of Emma as a brand, but this model happens to be built the way I'd build a boxed hybrid.
Gel and zoned foam over springs, with no memory foam to sink into
From the top there's a cool-touch knitted cover, 3cm of gel foam, 5cm of reflex foam zoned into three areas, 840 pocket springs zoned the same way and a 7cm reflex foam base, 27cm in all. The gel layer is there so you can move across the surface without sinking in. Expect to lie on this one, with a quicker bounce back than a memory foam bed gives you.
Zoning in both the foam and the springs is a sensible idea when the zones line up with your body. If you're very tall or very short, your hips can sit in the wrong zone, so the zoning helps least at either end of the height range.
The cover is treated with Purotex, which the listing says reduces the effect of dust mite and pet allergens. Take it as a fabric treatment and not a health promise; the practical bit is that the cover comes off and goes in the wash.
Who it suits, and who will find it too firm
Warm sleepers and combination sleepers are the obvious match. Gel foam runs cooler than memory foam, and a responsive top doesn't hold you in place when you turn over. Back sleepers of average weight should get on with it too, and the pocket springs keep a partner's movement mostly on their side. The owner reviews are few and nearly all happy; the one reservation is from an owner whose wife finds it a little hard.
That reservation is the one I'd expect. Without memory foam the shoulder gets less give, so light side sleepers should think twice. Heavier sleepers should avoid a boxed medium like this and look for a deeper spring unit and a firmer rating.
What to buy instead
If you want more sink and less bounce, the Emma Smart Hybrid Deluxe adds 4cm of memory foam and suits couples who sleep still. If you're a light side sleeper, a softer hybrid with a latex or memory foam top will treat your shoulder better. For a warm or restless sleeper set on a boxed hybrid, this is the Emma I'd pick.