Newmar builds some very nice motorhomes as well as some entry level rigs. You can refer to the original list price as an indication as to the quality of the components, including the cabinets.
As a rule of the thumb, diesels cost more and usually have better components, but not always. Some gas rigs have been very well made and with better quality cabinets. Some diesels are entry level with inexpensive cabinets. (I previously owned a Holiday Rambler Imperial Class C that had very well made cabinets as well as being very well made overall. I've had friends that had Holiday Rambler Vacationers (diesel) and were disappointed with the inexpensive cabinets.)