If you buy a lever machine (especially one that may need service), you better love to tinker!

I've had my La Pavoni apart more times than I can count.
I can't speak to the Cremina, but at least with the Pavoni, it's very sensitive to every variable. The biggest issue I have with mine right now is controlling the temp. I think that's where some of the higher $$ pro/consumer machines start to edge you out a bit. I have difficulty getting my lever machine to pull a shot as good as some of the local coffee shops. However, every so often, you get a beautiful shot from it. I'm still fiddling around with the exact grind/tamp, etc. I've also recently ordered a Reg Barber C-flat tamper in 49.6mm for it. We'll see if that helps stop some of the channeling issues I'm seeing. If it doesn't, then I may sell it and get something else.
One thing I will say about the manual machines is this: because you are the pump (i.e. you control the lever), you are able to, in effect, control the pressure profile (this includes stuff like pre-infusion, etc.). I find that to be the most appealing part of the machine (and how it looks of course). I've recently modified mine to allow me to control the temp a bit more, which seems to be helping. However, I haven't really had the time to mess around with it enough to see if that's going to have a big enough impact.
Another thing I will say is this: I don't think starting out with a lever machine (in order to learn about espresso) is ever a bad move. It forces you to learn all the different aspects of coffee. If you just start out with a pump machine and only learn how to grind/tamp, then I don't think in the end you will really have as much mastery as if you have been dragged through the mud by a lever machine
To use the manual vs. automatic transmission analogy (mentioned above), I think someone who is very good at driving a manual gearbox tends to appreciate more what their torque converter is doing for them, as opposed to someone who has only ever just jumped into a car, put it in "D" and pressed on the gas.
Just my view on the subject, but if you can buy the machine at a price where you can turn it around without losing too much money, then I say go for it. It will most likely be quite a learning experience for you and as far as learning about coffee/espresso, I don't think you will ever regret the decision, even if you later decide to sell the machine and buy a pump driven / computer controlled machine.
Ray