I’ve got both E39 and E61 versions.
As a mechanic that does work on the car myself i prefer the E39. Much better build, more mechanical rather than electrical etc so less to go wrong.
I’ve had the E39 for years, it’s just hit 136,000 miles and is still on the original clutch. I have replaced the entire front and rear suspension on it, and i mean everything at a cost of £1000. It does need front discs once a year though and the rear tyres (265/30/18) are a bit pricey.
Not too great on fuel though.
Other than that i haven’t spent anything else on it in 5 years!