Hi
Should i keep my toshiba tablet or should i buy the surface pro
Depends on what you want to do with it.
Windows devices have the advantage of more powerful software, more peripherals and better multi-tasking. Even in something as simple as watching movies or listening to music, this gives you more power and flexibility.
But _some_ windows software is better with a keyboard and mouse. Especially games (although there are enough touch friendly games unless you are a heavy causal gamer). In terms of full desktop software, touch support is not always a primary consideration - exceptions in things like adobe illustrator, fruity loops and some others including some desktop games. But generally if you scale the screen, and use some UWP apps, it's a good experience touch wise.
There is occasionally however an app that scales badly to a touch experience. But if you are using your tablet for general purposes, you won't really encounter this. I find some legacy software like my backup program scales wrong. I wouldn't want to use photoshop touch only either.
iOS has only touch friendly software. It's not as powerful, but it's generally more suited to tablets, and higher quality than android software. It's almost a middle ground - although you won't get the feature rich software even for basic uses, like you do with windows - full browser, full media players etc.
Android has only touch friendly software. It's not as powerful, the software isn't high quality, but it has a large catalogue of apps and a high degree of compatibility with Bluetooth smart devices.
So I'd say windows if you want power/flexibility in the software, iOS if you want to mainly play touch games or have low needs, and android if you want lots of smart device intergration. Windows does have touch games, and some great ones (trine 2, witcher 3, sims 3, icewind dale enhanced, torment enhanced, and many more) - but not quite as many as ios - if you want that volume, because you are a heavy casual gamer, then ios wins out (despite the fact that some of the windows touch games are better/higher quality). Of course plug in the keyboard or a mouse, or use a stylus, and that number goes up enough that IMO, windows wins out on number too.
Ultimately the surface as a two in one, can do more. It can be a laptop, or a tablet. With the stylus you can use that rarer mouse requiring software without needing a mouse, and there's a great deal of stylus intergration these days in windows (more than anything else). It's a high quality device, but it's expensive.
Me, I am on the side of windows. I've used everything, and I find the others limiting. Even browsing is inferior.
But I do get that using some full desktop software, without the keyboard is painful. How much that matters, really depends I think on how much of a power user you are. But if you do happen to encounter some software that doesn't work well with touch (which shouldn't be that often), just flip the keyboard on, no big deal.
For me, the big question about the surface range is price. I think you can probably get similar devices for cheaper. You get the surface, or the new dell or similar, if you want the top end.