@Paul Shannon - That is a pretty broad area, the cities you mentioned are really chunked up into a few distinct units.
1) Panhandle/High Plains - Lubbock (south end), Amarillo (north end) are the two main markets - agriculture and higher education based; Lubbock is on FIRE due to Tech growing rapidly. It has a growing vineyard/wine industry (see my other posts) and big white collar components, it does not track oil prices at all. The city is growing southwesterly/toward Wolfforth, buy in that direction for appreciation. Full disclosure, my brother @Matt Moreland is a realtor there. Amarillo is NOT a small city (unless you compare it to one of the metroplexes) and has adjacent Canyon with WTAMU and a good sizes student population, is adding the TTU veterinary school, and has a relatively diverse economy. These two cities are the main hubs for an area just north of Midland all the way to the Oklahoma panhandle and southern CO. Huge.
2) Permian Basin & Trans-Pecos - Midland to Big Bend area south, Big Spring west to Pecos. - This area is almost exclusively O&G based and will 90% track with drilling rig numbers and oil prices. Buy good deals that work when rents are low and stick with bigger markets (Midland, Odessa, Big Spring) and you will do fine and rake it in during boom times though. I live in Midland, there is still demand for rentals but you must buy the deals right to work in down times.
3) "West" Texas - Not "real" west TX (El Paso to Pecos), but that awkward in-between area from Abilene to Ozona that is between West TX, Central TX, and the Panhandle. - Somewhat tracks with O&G as it is on the edge of the Permian Basin and (especially down by Ozona) some older oilfields. Lots of agriculture and deer lease/hunting economic impact. Abilene and San Angelo have higher education and other economic impacts, they are up-and-coming markets and hubs for their area. Great tertiary/quaternary market options.
4) Real West TX - El Paso to Pecos - I don't know enough about this area to tell you anything, truthfully. El Paso is huge. I would avoid Pecos, it is on the western edge of the Permian and is almost 100% tied to O&G. Pody's BBQ is great though. The Guadalupe Mountains and Davis Mountains are sweet and you should go visit. Not at all what you would expect to find in TX.