I created a poster chart and just got it in the mail and want to report on it in case there are others who are wondering how those turn out. It took me forever to take the plunge and order one, I'll definitely be doing more..
I made a family tree chart and I added lots of stuff to it to make a sort of family tree history collage - photos, scanned images, records images, a map, and text boxes for obituaries and historical content (forcing it to tiny size 6 font, I worried about legibility). I added drop shadows some highlighting and used a few other tricks to highlight areas and cover over bare chart areas in one line that doesn't trace back so far. I wanted to toss it all on there because the whole concept was to share all those nice things I've scanned in as a collage with the pedigree chart there for context plus I wanted to test all these items to see how they printed out before considering doing more posters or a book. Well, all the tiny font I worried about is perfectly legible, the shadowing and layers are crisp and don't bleed into each other, the colors are perfect, the paper is a high quality and it came in a great heavy tube so I can safely reuse that to send it on to final destination.
Anyone hesitating to order a poster based on worries about whether it's really going to look right should inspect their work carefully to ensure they are submitting what they truly want and know that you really will get back what you send in. It's terrific, it looks even nicer in person than zoomed in on the screen - well worth the $20