I have 3 suits. When I started, I bought a two piece suit brand new from an online vendor (Rev***). They were actually a great company to deal with as I really bought 2 suits knowing that I'd return one based on fitment/etc. So long as you don't actually ride in it or remove tags, they were great for returns of this kind of stuff. It cost a little extra on a credit card up front, but they are very responsive in terms of refunds. There are other great vendors out there that are similar - I just didn't know my way around at the time. If you can actually touch and see the stuff - like with one of our local vendors such as Shagmoto, that would even be better.
My idea for a 2-piece was that I'd be able to use it for both street and track riding. I've never done it. Honestly, I don't do much street riding these days. You'll hear that a lot from many people. More track time results in less street time - for MANY reasons. I then picked up a used Alpinestars suit in my size (same size as the 2 piece suit). I've been wearing that as my primary suit - taking my 2 piece as a backup.
Last month I was fortunate enough to luck onto a very slightly used Heroic Stage III top of the line custom suit being sold by a very very nice gentleman who seems to have been (unfortunately for him) a clone of my size/dimensions. I bought it for less than 1/3 of the price he paid a year ago, and I wore it at Barber. It is incredible - I did not anticipate how much nicer it was. It fits snug everywhere, is much lighter, and I have a lot more flexibility. It is full Roo skin and Stingray, so I know I need to be a little careful with it but at the price - and because it just happens to be a perfect fit (much better than my A*) it was an awesome deal. I just shipped it back to Todd at Heroic just to have some other guys name removed from my butt (OK, waiting for the comments there - setup for somebody). Heroic is also fast and good at alterations, and their customer service is top notch. There is another N2 guy who's wife just bought him a new Heroic suit (not the top model, but VERY good) and when there was a slight sizing issue, Heroic immediately had a brand new replacement with 2 days. The Heroic suit is now my primary, the A* my backup, and I'm looking to sell the 2 piece suit.
BTW, I've also used Lizzy, and agree that she is very good, reasonable and is where I'd go if I wanted something done to an off the rack suit.
For under-suits, keep your eyes open at Cyclegear. Their "Heat Out" products go on sale a couple times per year, and when they do they are remarkably cheap and decent. I use two sets per track day (fresh set after lunch) just because they're so cheap and it's nice to get out of sweat drenched stuff at lunch and start fresh at 1pm.