Myself, I prefer a regional guide because I'm never sure where I'll end up in Southeast Asia. If I pack a country guide to Burma, then I'm sure to end up going to Laos instead, so I find it's best to have one overall guide for the entire region. If I end up wanting a specific country guide, I borrow it from a fellow traveler or buy one in country. These days all the major guidebooks are available in the larger cities of Southeast Asia. Budget Bias and Travel Styles Definitely make sure that the guidebook you bring on your trip is geared to your budget.
Most guidebooks have a budget bias.
For example, some guidebooks assume their readers have travel budgets sufficient for luxury hotels, French dinners and rental cars. The room rates for Saigon's deluxe Hotel Majestic aren't much use to me, but more well heeled travelers might want just that sort of information. The key is to know your budget and match it to the right guide. Just as guidebooks cater to different budgets, they also cater to different travel styles. Some guides are geared to younger travelers looking for nightlife, some to older travelers looking to shop.