Well if you look at it then XBl service offers three things:
1) Multiplayer
2) Party Chat
3) A week or two early access to demos
Beside thesse even XBL service is pretty barebones. I'm looking at a lot of people who believe that the service would've been worth it had they made multiplayer PS+ only (so weird). I mean just to make a service "look" more robust they should charge for something that has been free ?
I for one wouldn't actually mind party chat being PS+ only atleast as long as its just like how rumors state it to be (ie. requiring one premium member in the party chat at any time). The worst part is they may have a general lack of contents to offer.
Well those aren't the only offerings though possibly the only ones you'd be interested in.
There's also the Netflix integration (a few people I know bought an X360 just for that, and subsequently a gold membership), social networking integration (again know a few people with gold just for that), upcoming ESPN integration (going to convert a lot of Xbox silver members to gold members), etc...
I expect PS+ to follow that path in trying to integrate services that people want, and making sure everything new is PS+ only.
Even with that though, you can't argue that when X360 launched, the online multiplayer was pretty much the only reason for people to pay for gold service. Which then allowed it to get a large enough established paying user base to then support and fund the addition of all the other services that came later.
PS+ could use a similar push. By having at least one "must have" feature establishing the paying user base, and then expanding on services offered once they have a steady flow of revenue. That way you aren't always operating at a loss. But with their promise of online multiplayer always being free, they can't use their biggest carrot to draw users. So they are faced with the more costly prospect of having to deploy attractive services without revenue to support it in order to attract users to turn PSN from a loss leader to a at least break even or possibly a revenue generator.
Crossgame/Universal voice chat would be another big carrot they could use but they are either unwilling to deploy it (god only knows why) or unable to implement it to satisfactory levels. That could have been a big enough carrot to have gotten PS+ up and running with a large user base initially.
As it is though, I'm seeing a lot of wait and see until people feel the service offers something worth it to them personally.
Regards,
SB