Quality of lodging in general is decent.
Georgetown, the capital, unsurprisingly has far and away the biggest range of options, but here there are a number of problems. None of the "luxury" options in the capital - primarily the Pegasus and the Princess, have anywhere near the polish or charm to justify the hundreds of dollars they charge. On the other end of the scale are a number of tiny guesthouses and pay-by-the-hour places with lower prices. There are some great options in Georgetown, especially at the three and four star level. Hopefully the rising Chinese and Brazilian populations in town will lead to better options here.
In the interior, there are some amazing jungle lodges and camps, including those at the ranches and the south and the community-supported ecolodges in the middle of the country. Other developing options are community supported huts in Amerindian towns on the Linden-Lethm road.
The adventurous could try to get by with a hammock and paying small fees to hang it up in a benab. This isn't an option in Georgetown and will involve some planning ahead, lots of bug spray and wiles to accomplish.
Some small towns have basic guesthouses, which may or may not have fans, mosquito nets or other amenities.