The deadman switch on the Mirka Sanders & their clones can be a bit of a PITA. Extended sanding sessions can become tiresome when you need to manipulate the sander into a variety of positions. Sanding window frames in situ for example. It can also be a bit of a nasty surprise when you invert the tool for abrasive exchange & inadvertently depress the switch. I overcome this with a 6" length of electrician's tape over the switch: easily removed & replaced in a trice, & lasts a whole day at least, & allowing a whole variety of different grip positions.
I now have 4 Mirkas (2 DEROS & 2 DEOS, plus the DEOS Delta in cloned Dutch Delmeq livery). They're all significantly & noticeably lighter than the Festo/ol equivalents. Being significantly smoother running they're much less tiring to use for long periods too.
Efficiency is much higher than Festo/ol's equivalents. They all sand significantly faster, due I suspect to their core design for mesh abrasives (which also seems to capture dust better) & in the DEOS versions to a 20% larger sanding stroke. I occasionally use paper abrasives too (usually Klingspor), but generally much prefer the cleanliness, superior performance & longer life of Mirka & Sia mesh. The ceramic grades seem to work best of all.
Unlike Festool's requirement for (in many cases) their own brand of OEM abrasives with their own proprietary hole pattern , the Mirkas & clones will happily use abrasives (with even the weirdest hole patterns) from just about any Manufacturer, Festool included.
These new Mirkas & their badge-engineered clones have pretty efficient & powerful EC motors that seem much less prone to bog down over the brushed direct driven equivalents from other sander manufacturers, whilst consuming about half the electricity used by their competitors.
I still use smaller, much older delta sanders on occasion for fine & less accessible work. I eventually ditched my Festo Deltex in favour of an older Bosch model as F/tool abrasives (different hole pattern) are not so easily sourced. Standard pattern abrasives, in both mesh & paper varieties, are available just about everywhere. The Bosch also has a unique variety of fixed, angled & profiled sanding bases & fingers that makes it extremely useful & versatile for detail & reno tasks.
But the Mirkas aren't perfect either. I don't like the fact that Mirka (& Festool & Metabo) use those stupid "Plug-It" cables. I much prefer the reliability of fixed cables such as their Delmeq, Carshine, Indesit et. al. clones use.
I'd suggest you try the Mirka DEOS Delta for yourself. I consider it to be just "a better mousetrap", esp. with a roll of insulation tape on hand.