Hi lbtb,
Well, a lot depends on your circumstances. Are you new to diabetes and just using Glucophage (metformin) 500mg twice a day? Are you using more than two oral meds and approaching the maximum dose per day and still not achieving good results? Im not an MD so this is something you should really talk over with your Endocrinologist. My personal opinion is that if you are relatively new to diabetes and only on a single med at a fairly low dose, then exercise and diet are key and you should wait to see what happens with the disease progression before you make the Byetta plunge.
However, if you've advanced into diabetes where you need more than one med to get your blood sugar down, and its still not under 100 in the mornings (fasting), then you really should consider Byetta. Just realize that Byetta for most folks has the really really nasty side effect of making them seriously nauseous for awhile (can be anywhere from a few days to weeks depending on the person) until your body becomes accustomed to the medicine. I was one of the lucky ones and I missed that side effect. I was maxed out on metformin, glucotrol (glipizide) and avandia and by using 10mcg of Byetta I've completely gotten rid of the Avandia and cut my glucotrol (glipizide) and metformin doeses in half. All this and I typically run in the 90's for blood sugar when I get up in the morning and in the 70-90 range 2 hours after eating. Without the Byetta and only the oral meds I was lucky to keep a fasting blood sugar under 120 and two hours after eating could easily run over 200. So in my case the med is warranted.
There is one additional side benefit to using Byetta; it tends to actually rejuvenate your beta cells (they live in the pancreas and are responsible for insulin production). This being said, if you are early in Diabetes and not improving, a head start with Byetta could benefit by preserving more of your pancreas function longer term.
Just remember - It is almost assured to make you nauseous!!!!
Warren