So as many of you know I decided to switch to an iPhone 4S after years with my beloved N900 here are my findings:

Design
The iPhone 4S is very elegant, streamlined, and thin. I do not use it with a case, that being said - it is not the most comfortable headset. The N900 was MUCH more comfortable. The iPhone also appears to be much more fragile.

Hardware
The iPhone 4S is most useful in portrait mode, that makes it much easier to type with one hand, I got used to the lack of a psychical QWERY keyboard quickly. Siri is most definitely not a gimmick, it is extremely useful and very accurate even when driving with the windows open. One thing I dramatically miss is the LED light of the N900, that little LED was incredibly useful in retrospect. I was a bit disappointed that it only had mono speakers, but the sound is wonderful, I the speaker is better and louder than the N900 (surprisingly). The charging port is not pleasant, in the least - I miss microUSB. Battery life is also outstanding! I was shocked, better than my (overclocked) N900 (and I experimented with a few different types of batteries).

iOS 5.1.1
The design is really simple, too simple. For example I am unable to have numerous SMS messages open at a time. When confused on how to perform an operation one must think, "How would a really stupid person do this?" and it all becomes very clear. It is rather annoying. One feature that Maemo 5 and some Android phones are capable of is having the speakerphone activated by proximity sensor, I really wish the iPhone had that.

Siri is really amazing, Yesterday I was picking up some gold and weighing it and my buddy's sale was in grams and I wanted to know how many ounces it was. He said he had an app on his iPhone 4 but I just asked Siri, "How many ounces is 31 grams?" and "she" gave me a great/correct answer and had a good amount of detail along with it. It is also great for texting back while driving (hands free). Phrases such as, "Most of the anthropomorphic Gods of the Egyptians are bipedal" are very simple tasks even with a noisy background.

Software (Apps)
I rarely use Safari, if I need to check my bank account I can do that much faster through my banking apps, same with IMDb, eBay, Yelp, YouTube, etc.

Jailbreaking
After jailbreaking my device I researched and added some "hacks" - and by hacks I really do mean hacks. The vast majority of them are not properly made, the multitasking hacks don't offer you true multitasking, simply just another process running on top of the springboard. The multitasking is not really there, nowhere close to Maemo/N900, even when jailbroken. The tweaks/hacks are not nearly as well done or thought out as the ones in extras-testing or extras-devel. However, having an SSH and VNC server on the iPhone makes me smile, SSH however is no where as close to as useful as on the N900. After a month or so of having the device, I have not needed to restart it and it has not crashed once.

iCloud
I thought I was going to hate iCloud, but in fact I love it. As soon as I walk into range of my wireless network my phone automatically syncs all my photos/videos/whatever I choose and places them directly into a folder I designate on my PC. All this without iTunes. Huge thumbs up to Apple on this one.

Reflections
iOS does not have the soul that Maemo 5 has, it doesn't have that sense of customization and personal preference. It is not as refined as Maemo 5 is (surprisingly) either. Some things are really done poorly. But I must say overall, as a tool for communications, the iPhone 4S is vastly superior to the N900.

I don't miss the QWERTY keyboard, if I did I could just buy the case with a built in keyboard that is almost identical to the N900's keyboard. The two features I miss most coming from the N900 to the iPhone 4S is the LED notification and the use of the proximity sensor for automatic speaker phone.

Would I go back if they really pushed Maemo 6/7?
Truthfully, I gotta say, I don't think I would. iMessage, Siri, and it hasn't crashed/froze/or even hiccuped once (unlike the N900 that would freak out and almost freeze at times when getting a call).

Pleased with my decision, however I do miss Maemo, but when looking at the N900 it doesn't look that great when you're used to the iPhone 4S's incredible display, it looked dated simply due to the PPI, like a 1024x768 monitor from days of yore. If someone leaked the source to iOS, it would be very simple to make the best OS ever.