Schweizer too slow
Why does aircraft speed matter for training purposes?
I trained on the R22 because it was more readily available and less expensive than the H300.
After getting my licence I later did some training on the Bell 47 in Virginia and in Pennsylvania with Darren999 who posts in this forum. If I had my time over, and there was one available, I'd train on the B47. Slow, but the objective is learning to fly, not getting to a destination as quickly as possible.
I now fly the JetRanger and Gazelle. If cost isn't an issue, either would be excellent for training.
So for me at least that leaves the B206 at 3 times the cost of the R22 (given some operators require you to have a safety pilot to SFH, is that common?).
Some do, some don't. I've never been required to do so.
It often depends upon one or both of two factors:
One of the main concerns is the risk of a 'hot start'. There are two different systems - Bendix and CECO. Opinions differ about which is better/easier, but care has to be taken with both. Repair cost ranges from very expensive to astronomical.
The other is how well the operator knows you. Some schools are prepared to hire a B206 to a low hours pilot who trained or did a type conversion with them, and whom they trust, but not to a low hours stranger.
You mention getting an ATPL(H). If that's your ultimate goal, and cost isn't an issue, then B206 hours might help you stand out from other applicants when applying for a job. That's just an assumption - I'm not a professional pilot.
FL