My experience with IBOC (with a Boston Acoustics receiver) thus far is this:
1. The sound difference on F.M. is hardly noticable.
2. There is a difference on A.M. but whether or not the analog signal is topping out @ 5kc. could be a factor.
3. There's only 1 receivable A.M. IBOC signal in East Providence: WHJJ.
My experience in East Providence is much different than yours. I get three AMs in HD (550, when they were on the air), 1030, and 920.
4. The IBOC signals are so damn fussy & brittle it's like a highwire balancing act with fine china to place the antenna.
5. There were 3 HD2 stations that were receivable in E.P.: 93.3-2, 94.1-2 & 101.5-2. Nothing on 89.7.
How close are you to the WHJY tower? I think youre getting overload from it. Where I am in EP, Pawtucket Avenue near the Knights of Columbus (I walk down that way quite a bit), I can get the HD2s of the three you listed, plus 89.7, 98.5, 102.5, and 103.3, all using my Insignia portable. My "porch side" antenna picks up a few more. Get further from the WHJY tower (say in Riverside), and 94.5's HD comes in, again using the Insignia Portable. No fancy receive antennas or gear.
7. 93.3-2 occasionally has D.J.s but they sound like national filler. 94.1-2 hasn't had any that I've heard & 101.5-2 isn't operational anymore. It was some lame "comedy" channel (Joke Joke or something).
101.5-2 is indeed operational, its classic rock 94.1 and 101.5 both air Premium Choice programming, which have jocks, albiet from somewhere else. (I believe theyre in Cincinnati)
8. Ever since 101.5 installed IBOC, 101.9 has had a harder time coming in.
Only on the cheapest of cheap radios. My $30 alarm clock I bought from Nobody Beats the Wiz in 1996 has no problem picking up WCIB in my bedroom, which faces towards Rehoboth from the 3rd floor. In fact I don't think any of my radios have any problems with WCIB. I know they listen to WCIB in the Riverside Post Office using a Boom Box, without any problem.
9. From Taunton no A.M. IBOC signals were decodable. F.M. may have had marginal success but 93.3 was analog only.
In Taunton, I can hear everything from Boston in HD, and Providence, as well as Fun107, and WUMD. That is in Downtown Taunton using my in-dash player.
So I dont know , your experiences sound like the other extreme from what i've found.