Decking, cladding, general DIY. Would be nice if it came in a fancy box for storage.
I'm not made of money.
Off topic ramblings welcome.
Whilst I do have a mitre saw, before you spend the dosh, have you considered if a track saw might be more versatile ? A track saw is a hand-held circular saw linked to an aluminium rail to guide it. It can do mitres and angles etc too. Its key advantage is that it can do long cuts. I think Festool (a top quality but brutally expensive make) originated the idea, but Makita, Bosch and so on do them as well now at somewhat closer to a sensible price. Mine's a Festool and I think it's the best bit of kit I've ever bought - ie the track saw idea, rather than Festool wonderfulness.
View: https://youtu.be/xu85MUZwga0
Basically you can do long cuts as well as a lot of the the stuff a mitre saw can do, albeit the mitre saw is quicker and easier for short cross cutting. The track saw isn't really suitable for anything narrower than maybe a skirting board - I can't see it being useful for, saw picture frames.
I built these using the track saw, including the dado grooves on the sticky out side pieces (don't have a router), bearing in mind none of the angles of the alcoves are square.
I built a second (simpler) set in another room by which time I had the mitre saw as well which made the cross cuts a lot easier and quicker, but I still needed the track saw for the long cuts.
My mitre saw is a "sliding" type which allows maybe 10" width of cuts. A pure "chop" saw would only do 4 or 5", albeit you can flip it over and cut from the other side.
Whilst I'm a bit of a gear tart having bought Festool kit, even if you don't want to go to that extremem, there's still a lot to be said for buying "trade" or "pro" level quality - Bosch blue, Makita, Hitatchi etc as I'm unconvinced that the various Wickes own brands and the like are going to be up to
much (prejudice not experience admittedly) as I simply don't believe you can make a high precision tool for the money - and a mitre saw needs to be precise or it's only good for cutting firewood
To sum up, I probably do use the mitre saw more than the track saw, because of convenience for some jobs, but if I had to choose only one or the other, I'd take the track saw, as it can do nearly everything the mitre saw can, but also long straight cuts too.