Am I missing something - those monthly figures seem high, surely it would be possible to lease those cars for less? OK, there's insurance and maint included, but that wouldn't be much.
Even with the benefit of salary sacrifice, you're still 'paying' the £240/mth net allowance, plus £300ish per month - that still seems quite a lot.
I had a quick look at the Lex deals posted elsewhere this morning - E220 sport @ £311+vat. So that's £370 once the VAT is on. I've added on a few extras such as COMAND, heated rear seats, Harmon Kardon, etc, and I get to a base price of about £41k (working from an E250 AG). I've also got 25k per year mileage as I'm expecting more trips to the place in France, and have to bear in mind that clients are fickle beasts and may want me to work from their premises on a regular basis. It's also over 2 years, as I expect Master E to have his own car by then and we'll be doing something different.
I factor in insurance (in my case significant, as the company pick up the bill for the "first responder" insurance I need), maintenance, peace of mind (I have no off-street parking, for example, living in a twitten), no deposit to find, etc, and I can't beat it doing the deal privately.
WRT peace of mind, everything is handled for me. For servicing, the car is picked up and returned (essential when you live in the sticks), properly valeted (OK, usually standard with a Benz, but this applies to anything as it's part of the contract). New tyres - phone up and get them done. Snapped badged, keyed panels (as has happened with the current car) - one phone call and it's taken care of. RFL disc arrives in the post, comprehensive european breakdown cover (not that I've ever neeed it, but nice to know it's there).
It might not be the best choice for everyone, but there is often a blanket "taking the allowance is best" view that should be challenged based on personal circumstance. As it stands, come June/July I'll have a new car and will be £200/mth better off then I am at the moment (or a shade less if I decide to opt for the XF Sport). As is often said on this forum, it's the cost to move that counts.