I have Docs to Go and generally like it. Docs and spreadsheets are great.
In PowerPoint, slides with particular attributes render wrong. Graphics made up of individual lines and curves, even when grouped, don't come out well. Text in any orientation, other than horizontal, is changed to horizontal, making some slides very difficult to read/follow. I've gotten around these issues by doing screen shots of my slide, cropping in Adobe Photoshop and planting the entire image on the slide. But it's a hassle to do. Also, I avoid putting anything but horizontal text on my slides now.
Does QuickOffice HD have these issues in PowerPoint? I'd spend the $15 to find out, but I'm doing a lot of that lately. It's more about the time wasted than the money. Just a few days ago someone said their remote client was better than PocketCloud. I bought it. It wasn't. That was about the 5th time I believed someone saying one thing was better than the other. I've wasted the money, but again, more important was the time I wasted learning a new thing, only to find out it didn't deliver on the promises.
It seems there are a lot of people that "claim" to have experience in both, but really don't. Yeah, yeah, yeah... color all of you surprised. ;-)