Printroom is not known for being slow either...I don't know, maybe something else? Are you talking about the flash thing? Flash is cool but seems to add time to downloading pages. A personal decision about that, people have diff opinions about it.
In Jim's printroom galleries, how long a delay are you seeing between pressing the 'next' link above the image, and the image being fully visible in the page? I get 3-4 seconds. On my photo-engine system it is typically instantaneous. Those 3 seconds are a very big deal when you want to look through 500 photos.
My site is hosted on http://www.names.co.uk/. Have been using them for about 2 years now and been very pleased with both their service and technical support.
ifp3 looks really nice, although its still on the individual to print their own photos...which if i wasnt living in the middle of an ocean would be fine...but i could still use a good print site then send the out that way. nice to see a good flash based site though.
I forgot to mention that IFP3 also has a watermark feature that is really nice if you need to watermark your images instead of using a separate program