RAM limitation on non-Pro configuration

Hi, I heard MIUI reserves 1GB+ for itself. Can any of non-Pro version owners report RAM sufficiency for common operation (multitasking, running user apps in background etc.). How much complexity the present memory allows? Is killing apps in background frequent? How about lagging?
Is there any real test comparison between Pro and non-Pro configuration?
And finally is it worth to drop ~$30 more for Pro version (as about phone smooth performance and fingerprint scanner)

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