I own a 2006 Elise. I bought it new and drive it a fair amount (mine has about 36,000 miles on it). Here are my impression and experience.
The car is small and tight to get in and out of. With the top on it is a little bit of a pain. Once I am in the car it fits like a glove. I have taken it on week long camping road trips down the Blue Ridge parkway and around Deal’s Gap/Smokey Mountains and personally I think it is very comfortable to drive over extended periods. I’m 5’11” 180 pound, 45 years old, your miles may vary depending on your body shape.
It has been very reliable for me. With the Toyota drive train these cars are much more reliable than Caymans and 911’s. But they are more fragile. Mine is a fair weather toy, I have a Subaru Impreza for driving in the weather.
I do not think that the car needs more power. It is not ridiculously fast, but if you’re willing to abuse the clutch it can be fast enough from the line. It is more difficult to drive than a car with more torque because you have to shift gears more frequently. You have to keep it on the 2nd cam to make it go fast, but revving the snot out of it is half the fun. If you like a lazy V-8 with lots of torque you will not like the engine, and even a super charger may not be enough.
I have never driven a car with better road feel than this car. I moved from an MR-2 to the Elsise. I used to think that the MR-2 was a good handling car with great road feel, but the Lotus is in a world of its own when it comes to road feel. I am getting a little older, and I recently got married and got a nine year old step son with the deal. I was considering replacing the Elise with a 911 since in theory they have a back seat (ok, I know, but my stepson is not a big kid, and what nine year old is going to complain about a ride in a 911!) and more creature comforts for a middle aged man. I was looking at S.2 997’s, but quickly soured on them. The 911’s are faster cars, but are nowhere as much fun to drive. I am stumped at the magazine articles that I have read praising the 911’s road feel. Compared to the Elise they have almost none. They are much closer to my Impreza than they are to the Elise when it comes to road feel. I was hoping that the Porsche's would feel more lively and back happy. Maybe I need to look at 993’s instead (?). My dumb little Elise has ruined me. I doubt I will ever be happy owning any other sports car. Even Caymans and Boxers are unsatisfying to drive compared to my Elise.
If you are comfortable driving the tiny little thing (not scared about being crushed by a mom in a Grand Cherokee texting), love the road feel and are not put off by the fact that you have to rev the engine to over 6k rpm before it comes alive, and more importantly understand that “less is more”, then I predict that you will love the car. These cars one very much a min\max vehicle. And I think people will either love them or hate them. But if you fall in love with one, you will never quite be happy with any other car.