I'm running a PAQ-4C right now, and several guys I know run PEQ-2s, and PEQ-2As.
Here's the rundown...
Insight Tech makes the:
PAQ-4C IR Aimer ($1000-1500 for NIB, current market price)
PEQ-2A (ITPIAL) IR Illuminator and Aimer ($1500-1800 for LNIB, current market price)
NVEC makes the:
Vital-2 IR Aimer ($1800+)
ATTILA-200 Illuminator and Aimer ($???)
Almost everyone that has used both NVEC and Insight products prefer the NVEC hands down. With that being said, there is nothing wrong with either the PAQ or PEQ.
The OTAL-IR also seems to be a good choice, and IIRC they're running for around $800-1000 right now. Several people that I know that run OTALs are doing they believe the aluminum body is more durable than the Insight Tech's plastic body. I can't comment on that, because I've got no experience with the OTAL, but I have seen PEQs with cracked bodies.
Right now the problem isn't so much restrictions as it is availability. Even if you're LE you're going to be hard pressed to get anything right now.