We test all kinds of incubators and the brinsea octagons ar some of the best. In spite of all the technology i find the r com less reliable.
The most economical, reliable incubator is the corti. Buy them from the incubator shop, they are always good to haggle if the price isnt already the lowest you can find (they are usually the best prices around anyway). We use 2 big cortis as backup for our big incubator and find the hatchrate is as good as our commercial one. A corti should cost just over half the amount you will pay for an r com so you can afford an electric hen instead of a heat lamp (dont get a brinsea electric hen as it wont keep the chicks warm enough, go for the interhatch one, I think its called chick tech)
Once you get your machine pm me and I will help you with how to get the best results.
Dont try hatching yet though because we are still getting night frosts so cockerels will be firing blanks some of the time. Dont buy eggs on ebay this time of year as they are likely to be clear
Just in case you wondered, chicken breeding is what I do for a living, or at least a substantial part of what I do