I would personally recommend the scootababy over the ellaroo, for a number of reasons.

The scootababy has a unique windpro (fleece) shoulder that is very comfortable and supportive, it also can be worn on either hip without having to reverse rings or buckles (unlike the ellaroo). The adjustment mechanism is much simpler and therefore quick and easy to use, especially if your partner also wants to wear, or you want to quickly lower your baby for a feed. I know a few people with the ellaroo who have found it to be quite complicated to adjust, whereas I have had people who have never worn a child before use a scootababy without instruction and found it easy and intuitive. The waist is a heavily padded SSC type waist which is really supportive for toddlers (I have literally carried my 13kg toddler all day in one)

The scootababy is more expensive but for comfort and ease of use it is (IMO) a far superior dedicated hip carrier than anything else on the market. You might be able to pick one up second hand on either thebabywearer or baby-carriers-downunder for-sale-or-trade boards, which would make it much cheaper.

HTH!