i bought and Ipad mainly because of the Samplr app. It is now my favourite sample chopping tool, but I had to find a few workarounds.
Recording: The Ipad+Samplr combo cannot live without a good recorder. I simply cannot rely solely on the Ipad's microphone, except for when I'm fiddling with it. To keep things professional (and portable), I use a Zoom H1, a highly recommended and notably efficient digital field recorder.
Importing sounds: The first time I looked into that, I got scared. Some told I had to use Itunes, others told I could use dropbox. Hell, I couldn't go either way. I did some research and found out Fileapp pro, an app that allows you to import samples into the Ipad through usb or wi-fi (haven't tested the latter) without relying on Itunes. This app seems to be quite common among apple fanboys, so I gave it a try. It worked for me, I could transfer samples from my computer to the Samplr app folder, as well as open the recorded files folder used by the Samplr app inside Windows 7. The downside of all this is that you'd have to use a computer to intermediate the sample exchange process. There seems to be another way though, by using the camera connection kit, which is basically a usb/card reader adapter. I wonder if the Fileapp is capable of reading reading the Zoom H1 sd card through the camera connection kit adapter and import the samples directly to the Samplr app folder without the computer, but I'm yet to test that. On a sidenote, I read somewhere that Rode (the microphone manufacturer) will be releasing an stereo microphone expansion for the iphone/ipad, but I can't really guarantee if it will sound better than the H1.
Playing: No specific tips here, but one very general thought: I try to see the Ipad+Samplr as a musical instrument in itself. What I mean is that it requires time and practice to get the best results, just like any other instrument. I also try to use the Ipad exclusively as a music making device, so it helps a bit in that way. Now, sonically speaking, sInce we're talking about a sampling app, possibilities are virtually endless. I've had good hours playing with it, and each play mode gets you to different places. I don't see the Samplr app as an 6 track production sampling device, but more like a solo instrument, trying to get the most out of the samples I put in it.