In the normal mode, I was pretty indifferent to the system because i never died until after I had already purchased everything; however, Hero Mode changed my perspective a bit. After having my three/four heart pieces ripped away several times, I had to think more carefully about which items I absolutely needed. I also spent a lot more rupees in this playthrough. While many people claim the dungeons were too easy, I think this was due to their own design rather than being a symptom of the item rental feature. I believe they were intended to be played in a fast pace; while the games are obviously different, I had a feeling of playing Sonic at times in these dungeons - trying to constantly move without stopping.
I liked the fact that the special items in the dungeons were optional (Master Ore, new suit, sheild) but were key in upgrading your character. I felt less like "Oh, I have to find this item in order to beat the dungeon" and more like, "Oh, I really want to find this item." I think when a game makes you really want to complete content, rather than completing it just to get to the next part, then the game is successful at creating a great experience.\
I would like to see the system return, even if only for less essential/powerful items, but I won't be heartbroken if it does not.