Q: How portable will programs be across platforms?
A: Extremely portable, much more than C programs for instance.  You can run just about any XBasic program on any platform, unchanged.
Q: Is XBasic a P-Code interpreter like other QB, VB, and other development environments?
A: XBasic is a true compiler.  When you run a program in the program development environment, XBasic generates binary machine code into memory, then executes it.  When you make a standalone program, XBasic creates a binary executable ".exe" file that's loaded and executed like any other ".exe".   There's no interpreter of any kind in XBasic, no matter how you slice it.
Q: So XBasic is fast?
A: Yes.  Very fast. Compared to C, sometimes a little faster, sometimes a little slower.  Overall, about equal.  Compared to BASIC, or just about anything else, XBasic is alot faster.
Q: At what kind of programmer is XBasic targeted?
A: XBasic is as well suited to novices as programming wizards, and is appropriate for virtually all programming tasks.  For science and engineering, XBasic has extensive math libraries; built-in complex number data-types, operators and function library; and extensive graphics capabilities.  For business, XBasic has 64-bit integers, user-defined types optimized for database I/O, and comprehensive business graphics.  For system programs, XBasic replaces standard low level mechanisms with high level language alternatives that are much easier to read, understand, and maintain.   For all applications, XBasic supports rapid development of compact, efficient, reliable, readable, portable, well structured programs.
Q: If that's really true, why learn several languages?
A: Exactly!  That's one of the most important strengths of XBasic.   Learn just one language and write all your programs with it. It's the perfect lifetime programming language.
Q: What about OOPS?
A: There's no question that object oriented programming is a popular topic.   Just about as common are complaints by people who "don't get it" or think it's a hoax. Here's my opinion.  Object oriented programming is good for certain applications.  The most obvious is GUIs; they conform very nicely to the OOPS paradigm.  That's why OOPS has been a hot topic during the same time period as GUIs.   But not every application is addressed as cleanly by OOPS.  Complaints are increasing as OOPS is tried on every kind of programming.  The XBasic programming language is not OOPS, in that it does not explicitly contain OOPS features.  Still, you can write object oriented programs in XBasic, and GuiDesigner is an example.