I have been using several programs on and off (depending on customer req's and tied into various packages), from Eagle, Diptrace, CadStar, SeeTrax Ranger, Proteus, AD.
Eagle, for all of it's faults, has quite a lot of features, it can do length matching/meander and differential pairs (add to the name of one signal P and the other N for example), I would ask yourself WHY you want a different package?
Proteus and Diptrace can't do this, Proteus has a primitive length measure but you have to sort it out yourself (the last ver I used you had to anyway).
Yes, they may be "working" on it, but Eagle already does it.
I can understand not wanting to go TO eagle from another package as it does take some getting used to it's UI, but it's like everything, you have to work with it and get used to it.
Altium would be the only upgrade path I would go to from Eagle TBH, purely personal opinion. OrCAD might also be a good option.
Proteus is good at simulation, the others are just different. 9 times out of 10 people slate Eagle because they do not know how to use it.
KiCAD is getting better and better, but I wouldn't say it's better than Eagle if you have a Eagle license. If you are using the freeware version then KiCAD might make more sense from an unrestricting point of view, but people still complain about KiCAD's way of life.
For FPGA, well, Eagle can lay out QFP and BGA with no trouble, there are a ton of ULP's to do fan outs and the like, if you are after FPGA tools, well, stick with the vendor's tools (XILINX ISE, Altera Quartus II etc) as they are much better than the built in tools you find in Altium for example.
If it were me i'd stick to Eagle, and move onto AD or OrCAD if budget permits, overpriced for what they are, and Eagle in my opinion has a huge presence still in the industry you don't need AD to be an EE. One place I worked at switched from Easy PC to Eagle and they do military and aerospace cable test systems, no issues doing HV or HS designs with micro's and FPGA's.