HS2 was my first pin, really fun but could use a little more depth to help with longevity. I never bored of it per-say, but wanted something deeper as my collection will only ever be 2-3 pins max. I also like games with a good center shot, and HS2 is completely lacking in that dept - you never want to shoot for the stoplight targets directly imo... It's my second choice in that list.
JM is my pick in that selection,. Its a lot of fun, fast and good flow (imo) but some down time with the glove and scoop shot to catch your breath. I hope to own one myself at some point. Though I have very few plays on FT, the theme is a complete turnoff to me. NF is also but to a lesser extent.
If you can find a Judge Dredd that is another great choice in that budget range. Tons to shot for and plenty of variety. Was my second pin, one of my favorites...
I'd rethink the importance of theme in the fun factor calculations though - for me theme can make all the difference in modes and goals that I actually enjoy playing. Theme won't save a lackluster playing game either, but it's an important piece to my enjoying a game, especially long term.