The following brief guide might help you decide between ST-10, IDA-8 and IDA-16
Sound characteristic - ST-10 has the perfect balanced for people who is looking for some texture, warmth and yet detail and resolution in an amp. It also has gripping control and bass. ST-10 is the best you can get before moving upward to Reference 20.
IDA-16 is very well balanced and detailed. For entry level high-end audio, IDA-16 is a good place to start and you won't easily run out of power. It has everything you need, including a DAC with enough resolution and inputs that will not need any upgrade for the foreseeable future.
IDA-8 sound characteristic is between ST-10 and IDA-16. If you have high efficiency speaker, or bookshelf speaker in a small listening room, this is the best integrated amp on the market. I don't think anything below $2K would be able to compete with IDA-8. At $995 that also include bluetooth aptX and DAC, it is as future proof as you can get.
If you are looking for a reason to upgrade your old mini component or outdated entry level audiophile system, IDA-8 gives you everything you need in one box.