Tough call. The easy part of your question is...why buy a new standard class glider, ever? ;-). I certainly wouldn't. Less high speed performance, less climb, higher landing speeds and not really any easier to rig or less expensive.

Moving on...the HpH, from what I have seen and heard, has among the best finish quality in the business. Many recent buyers have been impressed. I think HpH will be increasing in popularity and is quietly selling a good deal of sailplanes. They are not necessarily aimed at hard core competitors, but if your putting FES on your sailplane, absolute top possible performance doesn't matter as much.

The Lak17b FES is also very strong. I have owned a Lak17a and found it highly under-rated by certain camps. The 17"b" suffers from the same. The 17"a" was designed as a 15m glider and the 18m tips were an afterthought (although it was still quite competitive in 18). It also had the limitation of a fairly low max wingloading (for 18m) of around 10.5 lb/sq.ft with a 15m based max gross weight of 1103 lbs (a ASG29 goes to nearly 12 lb/sq.ft and 1330 lbs in 18).

The '17b' FES fixes all of those limitations and then some. It has completely redesigned wing focused on 18m class but also at home in 15 & 21m. The horizontal stab, elevator, fin and rudder are all slightly larger to accommodate for 18m and 21m. The cockpit and many other features have also been improved over the years. Also, Lak has been building FES gliders for years now. The installation is very clean and extremely well thought out. There is no more reliable sustainer on earth than FES. Smart move to consider it.

Here are some pictures of a new Lak17b from the Ontario Provincial Championships held over Labor Day weekend this September. It was beautiful and the trailer arrangement (all three tips ready to go!) was genius.

If I had to choose it would be very close between the two. Safety cockpit is a plus. Laks experience with FES installations is important. I've heard great things about both gliders but I have not flown either. Getting the Lak in time to fly next season would be nice too. Might be worth a trip to Europe to see the factories and get more info...

Good luck in your decision. Honestly I don't think you can make a bad one.

https://www.icloud.com/sharedalbum/#B0VGQOeMmGCEx8j