I personally REALLY dislike the iD L, but since I dislike almost everything, I'm gonna recommend stuff to YOU, whether I like it or not.
If you enjoy the V4.5, well, I'm glad I'm not alone. That Shitekitchi just spolied EVERYTHING, on fifth generation too. If you're already considering the V4, I recommend that too. A V6 really would not suit you. The iD L seems to suit everyone except fussy people like me. I'm a fussy eater, fussy reader AND fussy Tamagotchi player, and the only iD L disliker on TamaTalk.
Overall, I'd go with a V3, V4 or V5. A lot of Tamas are what I describe as "a great Tama hidden under a veil of boringness", and if I could say one sentence to describe the V5, it would be just that. I got one V5, aged 8 or nine, purely for my mimi-collection, which at that time contained 8 or 9 Tamas. I thought it was the worst Tama ever; I hated the games, hated the no naming, hated getting bonding, hated the characters, hated the complicated growth. I was pretty careless about it, so I dropped it on the doorstep and it broke. A year later, I have a new V5, it is on third generation and it is my favourite Tama. But maybe the ID L and TAMA-GO are hidden under a veil of boringness too? And the many other Tamas I dislike? Who knows. Don't judge a book by its cover; don't judge a Tama by the first generation!
~ Dazzmina ~