I'd say something like 'Ghost Master is awesome and everybody should take this opportunity to play this underappreciated gem' but I've tried it before and nobody sodding well listens to me.
So whatever you do, make sure that you don't play Ghost Master. I'll be over here listening to ghoul_room.ogg on a loop.

Well I might listen to you and get it :P . Always looked at it whilst browsing gog catalogue, but not sure why I havent included it in my list. May have to get it now that its cheaper, but not sure I can afford it as I spent nearly 90 dollars last week here. Oh, Im sure I'll cave in anyways

That Ghost Master looks tempting, maybe I'll give it a shot.

Is gameplay in Ghost Master casual and linear ie. there's usually one fixed way to play through it, or are there multiple solutions? Does it have a believable setting ie. you get lulz from watching the residents get scared?

No, it's pure camp. As for the only-one-fixed-way, I'd have to answer with 'sort of.' Not sure how that makes it casual or not, though.

Well. Linear and linear - the objectives are set before each mission (plus a couple of "secret" objectives that you can discover during each mission), but you are free to choose from your accumulated collection of ghosts. The residents have a fair bit of randomness in how they react (although there is info you can use to predict, for example, what type of scare to use on a certain person most effectively), so you'll have to learn your ghost's abilities and adapt on the fly. Some of the more advanced objectives may require you to scare a specific person to a specific place in the house.
Some of the scares are pretty cool. Like telekinesis where you make everything that isn't nailed down fly around the room. Or Ghastly's (one of the "senior" ghosts) top ability ...
You can also get a first person view from any of the residents in a level. Cool for setting up more "cinematic" scares as you reveal a ghost to an unsuspecting resident just as he's passing the corner.
You can replay any level at any time, using newly unlocked ghosts - to for example complete the extra objectives or try to get a better rating for the level.
Also cool promo. Buying both.

Some of the puzzles have multiple solutions, and you're given a fair bit of freedom in choosing which ghosts to put in your team, which ghosts to spend points on upgrading, and how best to scare people off.
Also, while the setting is a bit of a parody of most other horror films (there's a blair witch level, a poltergeist level, a ghostbusters level, etc.), it's still fairly satisfying watching your patiently-laid scare plan work out.
Oh, I should probably add that I really loved the game, but it's not for everybody - there's more 'strategy' to it than actual 'action' (even if it does get very hectic towards the end).

Ghost Master, yes!

I own both on Steam already, but I'm very tempted to pick up Ghost Masters just for the extras and the ability to play it without the need of Steam. Just need to see if I have some spare cash =)

Ghost Master is fun, and definitely worth the current or original price.
Not perfect though. Control over your ghosts is too limited, sometimes it takes 15 minutes for a possessing or wandering ghost to stroll into the right place. Also, the solutions are not set in stone, but not every solution that makes sense is valid, which can be discouraging at times.
Still, I heartily recommend it. Also, the music is *very* good. And guess what, the soundtrack is a downloadable bonus!

For the price ghostmaster is worth the risk and I will probably pick up painkiller - after all shurikens and lightening who can resist.

I still say it's the worst weapon in the game

Can you elaborate on this?

Two good games. Very different styles, but I found each enjoyable.