The ergo is a great design but bulkier than the others you mention which are pouch slings (the ergo is based on the asian mei tai carrier, less bulky versions are babyhawk, ellaroo).
We have pouch slings and mei tei and ergo. They all have different uses. We found up till recently the mei tai best, but we have started to use the ergo more now as ds is heavier ( the ergo can hold the weight better for you back long term). The pouch sling is handy for up to 30 mins, I`d never wear it to walk to the shops, but I would wear the mei tai or ergo to the shops. All of them are worn around home and as for feeding, hmmm , well I am still trying that out. I did successfully feed ds when he was 3 mths in the mei tai when we were having lunch in a cafe, but so far I have not found it very easy to do.