Mariner is an excellent EM to play and the artwork is beautiful to look at. Some cool features with the pop bumpers, pop up post and return gate. I would have loved to see a spinner on the playfield. It has the "just one more go" factor and I loved having it in my collection. Parting with it was not an easy decision.
My first few games on X-Files left me unimpressed. But after a couple more games, something just clicked and I began to really enjoy it. It's a tough game and the ramp shots are tight, requiring accuracy. After purchasing one and putting many more games into it, I am really happy with having it in my line up. If you're a fan of the series, then you will be able to enjoy the game. I think it's underrated and the mixed reviews probably deter people. The multi ball modes are fun and the scoring is nicely balanced. There are lots of series references in the art and some excellent music and call outs during play.
I'd describe Counterforce as a pinball version of space invaders or missile command. The goal to hit all drop targets before the bombs / ships take out your bases is fun and adds some tension to play. The way the sounds speed up as the incoming missiles get closer also adds to the tension. The state of the drop targets is remembered between balls and players, which is nice. The only complaint I can put against the game is the speed - it just plays a little too slow.
Space Orbit is a fun single player EM. The game is an add-a-ball, with the main target being to activate the 6 roll over targets which allows you to store extra balls. The vari-target is nice and a rewarding shot to hit. It sounds simple to activate the roll over targets, but it takes some skill to get them all. It's a fast paced EM with some nice art.
Nugent is an excellent example of an early Stern Solid State machine. The playfield has plenty to offer with it's two drop target banks, spinner, bonus saucer, pop bumpers and free ball return lane. New machines enter my line up and some machines leave - but the Nugent remains and will for some time yet. A lot of fun to play and an excellent trip back to the early days of solid state machines.