Looking at a gulf stream conquest 255 with slide out and a 25lx heartland prowler no slide out. Rest of the features are about the same. Price the same. It's me my wife 2 girls 7 & 10. Plus two big do...
IMHO, the answer to your question depends on how you plan to use your TT. For us, the primary use was long, cross-country trips, so we opted to forgo a slide to save weight and preclude mechanical issues, etc. Our TT is also 101" wide, so there is plenty of space even without any slides.
Your needs depend on what you envision doing with your trailer, where and for how long. Good luck!!