I am currently playing my guitar through a keyboard amp and although the sound is fine I am looking to improve it. I am wondering if using an amp emulator would improve the sound. I am asking because I have never used one and don't know much about them. I have linked some of the ones I am considering (I haven't decided how much I want to spend yet). Thanks for the help.

1. Tech 21 SansAmp GT2: http://www.musiciansfriend.com/amplifiers-effects/tech-21-sansamp-gt2-tube-amp-emulator

2. Joyo JF-308: (a Marshall emulator) https://www.amazon.com/Guitar-Effects-Marshall-Speaker-Simulation/dp/B00NBV59Q0/ref=sr_1_10?s=musical-instruments&ie=UTF8&qid=1482826877&sr=1-10&keywords=Joyo+Ironman

3. Any other suggestions
Amp modelers are like any other pedal. Some you'll like some you won't. I've been using line 6 for years. Although I have 22 amps at my disposal. I found 3 that I liked early on and have pretty much stuck with those. Make a list of modelers and check them out on YouTube. Chances are you'll find something to suit your needs.
Dean Icon PZ
Line 6 Variax 700
Dean V-Wing
Dean ML 79 SilverBurst
MXR M 108
H2O Chorus/Echo
Valve Junior (V3 Head/Cab and Combo)
VHT Special 6
Phonic 620 Power Pod PA
Wampler Super Plextortion
Line 6 Pod HD
№1 and №2 were suggested for use in similar thread, as well as POD / Tonelab / V-Amp, you can check them too.