Putting a custom ROM onto an Android device is not as difficult as you think. The hardest part is rooting the device, but even then there are guides out there. Once you've rooted the device and installed ClockworkMod, it's simply a matter of powering up whilst holding down a key to get into the ROM manager, selecting a new ROM, and away you go.

I tried a few different ones out on my Galaxy S3 recently and in the end, putting a custom ROM on has made a WORLD of difference to the performance and battery life of my phone.

What did you go with in the end? I'm thinking about it for my S4 as Samsung /still/ haven't put out Lollipop in the UK.

Heh, still got the S3 at the moment and haven't really made a decision yet whether to replace it, or keep it for another year. I get married in under 3 weeks though, so replacing the phone hasn't been a top priority for now :)

53.12North: Sort of, only you're not normally replacing it with the stock OS that comes with the device. You'd have to check around online for your tablet. You'd be amazed what weird devices people have written these things for, so you might find something out there.