Harpa looks pretty expensive all-around, even with their discounts. Just my opinion.

I think the ROI on the purchase should be ideally higher for Merlin. But I do want Merlin to be so good that all in all it feels better to use Merlin in general.

I personaly use HARPA since last year and bough their LTD plan. I fint HARPA much more convenient for professional use, with a very high degree of customization and all the information is available at hand. Their UI is a thousand times smarter than Merlin.

Merlin is the cheap version of Harpa, with a few extra and many missing features.