Hi Claire
I had six chemos and unlike Sam, my treatment was not continual. But like you both, my veins were dicky so I had the port surgically implanted prior to the first chemo. (It took about four nurses to get blood out via my veins, so there wasn't much choice really.) The procedure to insert the port was relatively simple (compared to everything else we go through!) and also the removal was simple.
The downside for me, was the scarring - I scar badly (keloid/lumpy scars). Even after having the scar re-done, it still looks a bit unsightly. However, I know other women who scar well, and their port scars are nearly invisible.
In saying that, if I needed to have another port, I wouldn't hesitate - it is so much less easier and less stressful than being a pin cushion with collapsed veins. The port patch (numbing cream) made using the port completely painless each time I had chemo.
Hope that helps with your decision making. Good luck for your treatment.
Cheers, Kym