We have had very positive experiences with Bob Richter. His IN-SYNCH product has more data integrations than most need, but that's one of the reasons it's so good. Over the years he has added what has been requried. Some would think that ROI being a small company would be a negative, but Bob many times will personally resolve issues, even when they are not directly his issue.
We can point to Web Services as Sage's current method of integration, but it is not as complete as IN-SYNCH, and most of the time you have to call on someone to do the actual integration.