Do u feel it would still be a good upgrade today? I am running iOS 10.3.2 on it. Thanks.
How do you feel it runs - is it fast enough?
To me, that question has two parts. (You may see it differently...)
The first part is: is it a good upgrade technologically, is it worth the cost of the Mini 4 minus whatever you can sell the Mini 2 for? To me, yes, no question. The speed and display improvements were very noticeable, but other people don't see any difference in the display - although DisplayMate did an objective, quantitative comparison that showed the Mini 4 way ahead of the Mini 2. Still, depending on your vision and your uses, you might not see it or you might not care.
The second question is harder: is it a good upgrade today, given what we don't know about Apple's plans for the Mini line? I don't know. If you sink a few hundred dollars into a Mini 4, which is getting kind of stale technologically (though still a lot fresher than the 2...), and they introduce a Mini 5 next spring, are you going to be kicking yourself? I don't think I would, personally, but I did get burned that way when I bought an iPad 3 and Apple introduced the iPad 4 five weeks after I bought it. Still, five weeks is different from five or six months. The other side of that is that the 4 may be the last Mini - but in that case, it will still be available in the refurb section for quite a while. Which is another way of saying that unless you REALLY need an upgrade NOW, you don't risk much by waiting until March or May of 2018.*
*The one thing that you would lose is the chance of getting a Mini 4 that was running some version of iOS 10 rather than iOS 11. Right now, odds are probably pretty good that a new Mini 4 comes out of the box with 10.x. Next spring, it's almost guaranteed to come out of the box running 11.x. I had 11.0 and 11.0.1 on my Mini 4 and was not thrilled by the performance hit. Other people don't feel that way, though, so we're back to personal judgments...