I used to fly the Lineage from 2009 until last year, including the very first one.
It's a decent aircraft, but it has its quirks and issues. Reliability is pretty good. This aircraft was originally designed with high cycles in mind.
We had some growing pains with the first one with the refueling system. As a result, Embraer put out a SB which 'addressed' the problem, but didn't quite solve it. Basically, if you want to take on max fuel, you have to "reset" the refuel system and have the SOV do their self-test before you take on the last 5000 kg's. I believe this was going to be addressed in one of the subsequent Loads, not sure if it was as the aircraft I flew after the first one had the same problem.
Performance-wise, we generally didn't have any runway performance issues - we used APG for our runway analysis. If you depart at MGTOW, you'll be stuck in low to maybe mid-30's initially. That can be a drag. We'd usually cruise at .78 unless doing max range in which case, we'd do .76. The longest flight I've done on it was 9 hours 25 minutes (Beijing - Bahrain). I'd say range is kinda on par with G-450. I think 4,500 nm that Embraer advertises is a bit enthusiastic, though they've done Mumbai - London. I'd love to see how much fuel did they land with.
The cockpit is very roomy and comfortable. Take it from a 6' 7" guy... it's much roomier than the BBJ.
Here are some of the issues with the Lineage.
No external airstairs access. Yes, that's right... You'll be able to drop off the client, but then you'll have to figure out how to secure the aircraft. Now, as weird as it sounds, we haven't had any significant issues with this. It can suck for the crew, especially if you're at some podunk airport with no stairs and you have to use maintenance steps to get down after securing the aircraft for the night.
The tow bar. It's highly impractical to take with you. Your best bet is to ensure that your destination will have an E-170/190 tow bar if you'll be required to do the pushback. If you have to carry your own, then the pushback, disassembly, and storage is at least a 30-45 minute job.
The shower (an option on one of the aircraft I flew). If you get a shower option, you'll lose about half of your baggage compartment. Without the shower, you'll have plenty of baggage space. With shower, it will get cramped as it's built into the baggage compartment. In a year and a half that I've flown the aircraft with the shower, not one person has actually used it since we took delivery of it.
PATS DeCrane interior workmanship sucked in the first aircraft! Embraer took it in-house, and they haven't been that much better with the second aircraft. They might have improved it in the last 2 years.
All in all, Lineage has a very nice ramp presence. It's a sexy looking aircraft. Your boss will probably like it, depending on your mission. You on the other hand coming off of Global, well... you'll learn to like it.
I can go into a lot more detail, but this is just the basic overview.