You will find that to get a good espresso you need to control a few variables, and a clean machine is just one of them.
In fact I read somewhere that a good espresso is 20% machine, and 80% barista (I think that covers the part where the human chooses the beans, the grind, and all the other human intervention).
Hard to lock in the portafilter could be becos the basket is overpacked? *Try putting in less grounds.
Lack of crema might not be due to the machine. *When I was using my Classic 2 weeks ago, I was getting good crema out of it. *Check the quality of your grounds, what is the pour rate? *The grounds could have been ground too coarse. *Are the grounds stale? *Did you tamp with enuf pressure?
With semi-auto machines, the great thing is that you have control over all the variables, the flip-side is ... if you dont care about them, your coffee is a hit and miss affair.
Yes .. throw that silly crema enhancer away, I think mines still in the plastic bag! *
Let the machine warm up with the portafilter in place as well, a key part to great espresso is stability in temperature as well.
Hmm I dont know how to upload a picture here. *But give me your email and I will send you a picture of the shot I pulled using my gaggia.