Ok, so I've played with both enough to make a final decision and in the end Mehdoh won, here's why....
Clean and Simple vs. Flashy and Busy
Gleek was just a little too busy for me and I really liked the clean and simple look of Mehdoh. I also liked how Mehdoh was well integrated. I liked how I could just swipe across to see my timeline, mentions, messages, friends and followers. I also really liked how each list I made was individually on top as well which made it quick and easy to see. With Gleek, I had to go in and out of tiles. If I was looking at my timeline or mentions but then wanted to look at a list I made, I would have to exit out of the timeline and mention tile then click into the lists tile. I just got tired of going in and out of the tiles within gleek.
Also, I felt that Mehdoh had smooth transitions as where Gleek was a little laggy and choppy; I think it's bc there's so much animation going on within the tiles of Gleek app but that's just a pure guess.
Toasts
I noticed my Mehdoh toasts would always work whereas the Gleek toasts never showed up. However, when you turn on the toasts option for Gleek it does mention that you might have to turn off toasts for other apps in order for the Gleek toasts to work. I just didnt like the fact that I had to turn off other toasts options on my other apps when Mehdoh worked perfectly fine without me having to do that.
Links and Pics
I really liked how mehdoh displays links and pics. If there is a link or pic within a tweet you can swipe across to see the pic or link to a website all within the tweet! It was pretty neat. If there was a link to a website within a Gleek tweet, it would just open up IE. I forget how pics are revealed within a gleek tweet, but I THINK they just pop up within the tweet if Im not mistaken.
Live Tiles
I actually liked the Gleek Live Tile better than the Mehdoh one. Gleek would show the number of messages and mentions you had even if it was zero, as where Mehdoh wouldn't show you anything till you actually had a message or mention. I don't know, seeing the number zero satisfied me more than having to look at a blank live tile hahahaha. I would also say the gleek live tile would flip more compared to the mehdoh tile.
Overall
Both apps are pretty similar in terms of what they have to offer with Gleek having a few extra features (gleeks, peeks, ringtones, color codes, etc) but personally for me, those extras just weren't enough for me to keep Gleek. Don't get me wrong, gleek is a real good app and I think if you're a hardcore twitter user you'll like it, but for me, Mehdoh just works.
Thanks again for everyones replies and opinions, I'm glad we have a good and active community here.