I had a generic tamper with my Nemox which had a bit of play, and I found I was getting a donut style extraction, ie the outside of the basket was favoured by the water, obviously the grinds were not being sqashed very well at the very edge due to the slightly loose tamper fit.
When I got another machine, I got Synesso baskets and a fitted Pullman barista tamper. The extraction is much more even (all viewed with naked PF), and its like chalk and cheese comparing the quality and feel of the 2. The Pullman feels great to use. I do rarely get the tamper to be a bit tight when pulling it out, but this generally only occurs if I have overfilled the basket, and is significantly reduced/eliminated by twisting as you pull out.
The other thing to keep in mind is that if you have a 58mm style machine, investing in baskets and tamper should last you a lifetime, as for most of the 58mm machines the baskets will be interchangable. So you can keep your baskets/tamper when you upgrade machines in the future.