Dish has 4 different menu designs:
1A - the original primitive looking menus used on the x000, 3700, and D-VHS. No PIP or sound on any menu or EPG, must press Info to see program description.
1B - the OpenTV modification of 1A used on the x900, 301, 50x, and x11. PIP on the guide, menu buttons have rounded edges (woooo). EPG can be 6 lines/no PIP (modified primitive) or 4 lines with PIP.
2 - a non-Dish design, the WebTV interface of the 7x00. A well laid-out design with 2 sizes of picture on most menus (small on most) and just sound on most of the rest. EPG shows 7 channels and displays program info next to the PIP. Couple of problems here are that menu options are not numbered so anything you want to do requires multiple key clicks to navigate the screen, also when the box is turned on it defaults to showing the menu rather than full-sreen TV.
3 - The layered menus of the 721/921. The picture remains full-screen while the menu options expand over it, much like going to Start>Programs>Accessories. Same EPG options as 1B but also displays program description next to the PIP.
4 - 322/522/625/942. The menu is listed vertically like #3 but the current program is reduced to a small PIP off the side so there is no obstruction. Also IIRC the menu options expand in the same space instead of across the screen. Same EPG options as 1B but also displays program description next to the PIP. The 942 adds some new EPG options of 3 hours wide for TV1 and 1-hour with large text for the visually impaired and/or those with small screens. On DVR models, "Browse Plus" allows line at a time browsing of the whole EPG, not just current and next show, over a full-screen picture.
I have owned 1A, 1B, 2 and 3 but like 4 best.