I do both. I usually log the flights on paper right away, and enter them into Logbook Pro whenever it's convenient. LBP is really just a backup for me, and it's also easier to have it calculate the "hours in the past 90 days" than it is to go through the paper log. It's also useful to add your own time columns. e.g., I have a column labled "X-C 50+" which is my XC time thats 50+nm (still logging it for ATP). My paper log obviously doesn't have that, all XC time is lumped into the XC column... but in LBP, I'm able to seperate it as needed.