We usually advise users to wait until the first service pack or x.1 version of software is released. Windows 8.1 is going to be available to current Windows 8 users in a couple of months. It is a good time to upgrade or replace.
Should you upgrade or replace? Generally if your still running Windows XP on your computer then it would be best to replace. If your using Windows 7 you could possibly upgrade your current hardware to Windows 8.1. Each situation is different. A Lotus technician can remote into your computer and tell you if your hardware is ready for Windows 8.1.