Root

[#1]

There are a number of programs that allow rooting of your device but is there one that stands out above the rest ?

Can rooting your device have any affect on apps already on your device ?

[#2]

Well I know my bank app (Barclays), warns you on a iPhone that it won't run on jailbroken ones.
No I haven't tried it 

I would imagine it would depend on the app and whether they have put something in to detect it. Persumably they could put a check in which would otherwise fail on a more restricted device, but if it then works then refuse to run.

[#3]

Whatever device I'm messing about with my usual first port of call is to look on the XDA Developers forum here

Last device was a very cheap Nook HD+ which makes a nice standard 9" android tablet with a full HD display with the help of cyanogenmod

Not bad for £9

[#4]

Things like banking apps, & android pay will not run on rooted phones.
As to specific apps to root, nope depends on the unit, somethings work on some and not on others.

[#5]

Yes if you can get hold of a cheap device running the same OS - it may be worth getting one and having a play, just for the fun of doing it and see how it is. Then test what runs and what doesn't and the difference.

If it is your main phone, I would hold off doing it in case it breaks something (i.e. banking Apps) which I guess as Apps go, most of us have to use and depend on them. 

I don't know about Android phones as have never had one of those, and whether the root changes can be reversed easily should it not go well.

[#6]

I've used Magisk on LineageOS 14.1 to use TSB banking app & Android Pay on a rooted phone I keep as a back-up.

[#7]

My advice would be:

Firstly what do you gain to benefit from it?

Yes it might be good fun and a laugh to do it, but otherwise.

If your bank apps stop working how much of a pain would it be for yourself, and then looking for solutions to make them work.

It it were me, I’d pick up a cheap Android test device and do whatever you want to it and don’t touch your main phone until you’re confidient it works in the way you want.

[#8]

When I first rooted my phone the objective was to get rid of junk and be able to fully back up and reinstall programs/data. Other things like the Nook it's to turn it into a standard android tablet and the Hudl get rid of Tesco.

As for some apps stopping working I've not seen that myself but I have seen some "roots" that come with an on and off option.

[#9]

@billnotben 

I've also got a rooted Nook HD+, running a Cyanogenmod version of Android 4.4.4. It is somewhat flaky at times, rebooting itself at random. I don't know if this behavior is OS or hardware related. What version are you running?

[#10]

I have 4.2.2 on mine. Seems pretty stable with just the odd rare bit of bad behavior.

Though I guess this is probably down to what you are trying to run as the hardware can't be what the software is expecting.